USSBS Report 54, The War Against Japanese Transportation, 1941-45

8/3/2019 USSBS Report 54, The War Against Japanese Transportation, 1941-45

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THE UNITED STATESSTRATEGIC BOMBING SURVEY

C;

The War AgainstJapanese Transportation

1941-1945

Transportation DivisionMay 1947


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THE UNITED STATESSTRATEGIC BOMBING SURVEY

The War AgainstJapanese Transportation1941-1945

Transportation DivisionMay 1947

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U. S. SUPERINTENDENT OF UOOUAiLkIS

JAN 21 1948

This report was written primarily for the use of the U. S. StrategicBombing Survey in the preparation of further reports of a more compre-hensive nature. Any conclusions or opinions expressed in this report must beconsidered as limited to the specific material covered and as subject to fur-ther interpretation in the light of further studies conducted by the Survey.


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FOREWORDThe United States Strategic Bombing Survey

established by the Secretary of War on 31944, pursuant to a directive from

late President Roosevelt. Its mission was toan impartial and expert study of the

of our aerial attack on Germany, to bein connection with air attacks on Japanto establish a basis for evaluating the im-

and potentialities of air power as anof military strategy for planning the

development of the United States armedand for determining future economic pol-with respect to the national defense. A

report and some 200 supporting re-containing the findings of the Survey in

have been published.On 15 August 1945, President Truman re-

that the Survey conduct a similar studythe effects of all types of air attack in theagainst Japan, submitting reports in dupli-to the Secretary of War and to the Secre-

ary of the Navy. The officers of the Surveyits Japanese phase were:Franklin D'Olier, Chairman.Paul H. Nitze, Henry C. Alexander, Vice

Chairmen.Harry L. Bowman,J. Kenneth Galbraith,Rensis Likert,Frank A. McNamee, Jr.,Fred Searls, Jr.,Monroe E. Spaght,Dr. Lewis R. Thompson,Theodore P. Wright, Directors.Walter Wilds, Secretary.

The Survey's complement provided for 300350 officers, and 500 enlisted men. The

military segment of the organization was drawnfrom the Army to the extent of 60 percent,and from the Navy to the extent of 40 percent.Both the Army and the Navy gave the Surveyall possible assistance in furnishing men, sup-plies, transport, and information. The Surveyoperated from headquarters established inTokyo early in September 1945, with subhead-quarters in Nagoya, Osaka, Hiroshima, andNagasaki, and with mobile teams operating inother parts of Japan, the islands of the Pacific,and the Asiatic mainland.

It was possible to reconstruct much of war-time Japanese military planning and execution,engagement by engagement, and campaign bycampaign, and to secure reasonably accuratestatistics on Japan's economy and war produc-tion, plant by plant, and industry by industry.In addition, studies were conducted on Japan'sover-all strategic plans and the background ofher entry into the war, the internal discussionsand negotiations leading to her acceptance ofunconditional surrender, the course of healthand morale among the civilian population, theeffectiveness of the Japanese civilian defenseorganization, and the effects of the atomicbombs. Separate reports will be issued coveringeach phase of the study.The Survey interrogated more than 700 Japa-

nese military, government, and industrial offi-cials. It also recovered and translated manydocuments which not only have been useful tothe Survey, but also will furnish data valuablefor other studies. Arrangements have beenmade to turn over the Survey's files to the Cen-tral Intelligence Group, through which they willbe available for further examination and dis-tribution.


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PREFACEThe study of the history of Japanese mer-

chant shipping presented problems of veryconsiderable difficulty, largely because of theconfusion and inadequacies of Japanese records.Most of the Division's work was necessarilydevoted to culling out material of sufficientquantity and validity to provide a reasonablyaccurate description of this phase of the Japa-nese war effort.

Statistics regarding the sinking of Japanesemerchant shipping are based on infomiationcollected in Japan. About fifty different lists,reports, and other pieces of information wereobtained from Japanese Army, Navy, and civil-ian sources in Tokyo and elsewhere in the em-pire. Some of this information purported tocover the whole question of the fate of theirmerchant marine; some dealt with only certainsections of the problem, geographically, chron-ologically, or in accordance with other limits.Not one of these lists is believed to be completeor accurate within tlie limits it is alleged tocover. However, the source material representsa sufficiently broad cross section of informedpersons to give a comprehensive picture of whathappened to the Japanese merchant marine. Allof these pieces of information have been com-pared, checked, evaluated, sliip by ship, andsubstantiated wherever practicable by compari-son with attack data from United States sources.

The governing policy in making this tabulationof Japanese merchant ship losses has been todevelop an over-all picture of events sufficientlycomplete and accurate to justify general con-clusions on the subject. It is believed that thishas been done. It is believed that the statisticsin this report cover the fate of at least 9.5 per-cent of the merchant tonnage under control ofthe Japanese and that within that coverage thefigures are at least 95 percent accurate. Becauseof the lack of time and the comparative un-reliability of the data available, no attempt hasbeen made to survey, ship by ship, the losses ofshipping under 500 gross tons burden. However,it is believed that this small shipping played arelatively unimportant part in the workings ofJapan's war economy. (The order of importanceof steel shipping under 500 tons is shown inthe fact that it constituted only 3 percent ofthe steel merchant tonnage available to Japanon Pearl Harbor day, and that during the warless than one-half of one percent of the steeltonnage constructed in Japan was less than 500tons). Full information on individual ship sink-ings will be available by reference to reports ofthe joint Army and Navy assessment commit-tee, not yet completed, whose findings representa careful appraisal of all available data and aremutually agreed to by all the services.

i


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TABLE OF CONTENTSChapter Page

I. Summary and Conclusions 1II. Transportation in the Peacetime Economy of Japan 13

III. Prewar Transportation Facilities 26IV. The Attack on Transportation 34V. The Effects of Attack on Transportation 45VI. Transportation in 1945 83

VII. The Economic Effects of the Attack on Transportation 99Appendix PageASubmarine Sinkings of Merchant Tankers 113BConsolidated Recapitulation of the Japanese Merchant Ship Situa-

tion During the War (Tankers Excluded) 114CRecapitulation of Japanese Merchant Tanker Situation MonthlyDuring the War (Tankers Excluded) 116DWeight of Attack Against Shipping.. 117EStatistical Summary of the Attack on Transportation 118FTransport by Shipping under Civilian Control During the War 133GPort Activity of Major Japanese Ports During War Years (1942-45) """^p.'


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_ 0HUPEUl HARBOr ^

MMIM t eiLBERT


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MANCHURIA

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YELLOWSEA

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JAPANANDVICINITY

EAST CHINASEA

PACIFICOCEAN

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CHAPTER ISUMMARY AND CONCLUSIONS

No major power in the world was more de-upon ocean shipping than Japan. Her

economy in peace, and even more so independed upon shipping to provide thematerials for industry and to fill out theof staples required to feed and clothe

population. The munitions industries werefounded upon the basic iron and steel,

and chemical industries, all of whichheavily upon imported raw materials-

ore, coking coal, scrap and pig iron, alu-phosphorite, etc. Although some basic in-

raw materials were available in theislands, they were largely of inferiorand inadequate output. In fuel alone,was reasonably self-sufficient for ordi-

industrial and domestic purposes becauseher large coal reserves and developed out-But coal of coking quality was lacking andall-important oil to power her Navy, mer-

marine, and air force had largely to beAs a maritime nation with a large domestic

foreign trade, as a great naval power, andan aspirant to conquest, Japan had devel-

a large and modern merchant marine.the active interest of the government, the

fleet had been built up to 41/0 millionin 1937 and was carrying some 54 percent

the nation's foreign commerce, in additionthe entire volume of its large domestic and

trade. Even so, Japan was short ofat the end of 1938 only three-tenths

one percent of her merchant fleet was laidas compared with 3 percent of England's10 percent of the United States merchantActive shipbuilding in the modernization

expansion of this fleet had given her a siz-and competent shipbuilding industry. Theof large ocean-going vessels was supple-

by numerous smaller craft ubiquitouslyin the coasting trades between and

the home islands. But as her shippinghighly developed and her principal heavy

located to employ fuel and raw ma-received by water, the railroad mileagesmall and the rail system was generally of

limited capacity. Only two main lines extendedthe length of Honshu, keeping for the mostpart close to the coastal margin. Only the linefrom Tokyo southwest to the great ports of theInland Sea and the Shimonoseki ferries wasdeveloped for heavy traffic. The few laterallines crossing the backbone of Honshu were ofmost limited capacity and of minor importance.On Hokkaido and Kyushu the system was oneof gathering lines feeding into the ports andferries. Only after the war began was directphysical rail connection secured between Kyu-shu and Honshu by construction of the Kan-mon tunnels. In normal times the rail systemhad a large predominance of passenger busi-ness and its freight traffic was chiefly of theshort-haul variety largely ancillary to the coast-wise and ocean movement. The highway systemwas primitive and no important improved in-tercity highways existed. Intercity truck andbus transportation was completely undeveloped.The disposition of fuel and other natural re-

sources in the home islands concentrated thesources of bulky domestic traffic at the twoends of the main island chain, i. e. on Kyushuand Hokkaido, whereas the principal popula-tion and industrialization was along the south-east coast of Honshu from Tokyo southwest-ward to the great ports of the Inland Sea.Coastwise shipping and the two limited-capacitymain railroads were the life lines of the basicdomestic movement, particularly of fuel andfoodstuff's. These life lines proved to be exceed-ingly vulnerable.The series of events following closely upon

Pearl Harbor culminated in a vast expansionof territory under the control of Japan, a widescattering of her armed forces in the field, andthe imposition of formidable problems of sup-ply by ocean vessel. Simultaneously the countryfaced the problem of exploiting at once the re-sources of conquered territory, all separated byocean hauls from the main islands, in order totake the place of the prewar import trade andreestablish the raw materials and food basesfor the Japanese war economy. But Japan hadbeen gradually deprived of the use of foreign


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shipping prior to Pearl Harbor and had takenonly 823,000 tons in her conquests. The Japa-nese shipping situation was, therefore, tight atthe very beginning of the war, and it wasnecessary to press the utilization of the mer-chant fleet to the maximum. The fleet of ocean-going steel ships, because of a vigorous con-struction program, had expanded by this timeto some 6,000,000 tons, (of ships over 500 tons)but nearly 4,100,000 of these were assigned tothe military in separate Army and Navy poolsleaving but 1,900,000 tons in the civilian ship-ping pool. The rapid expansion of conquest andthe development of reverses at the peripheryprevented the expected return of vessels fromthe military pools to civilian use. The threepools continued to be separately operated. Aneffort was made to have vessels in the militarypools load strategic materials on the returnvoyage to home waters, but this was generallyunsuccessful and the amazing spectacle of shipsmoving in ballast in opposite directions in theface of a severe shortage of shipping continuedvirtually throughout the war. Shipping was anearly target for Allied offensive power. Evenduring the retreats through the Philippines,Malaya, and the Indies, significant damage wasdone by Allied air power and the submarinessoon began to harass Japanese shipping lanesfrom Tokyo to Singapore, albeit in weak forceand scattered fashion. Nevertheless, despite allof Japan's shipbuilding efforts and despite theweakness of available Allied offensive forcesearly in the war, the balance of shipping avail-able to Japan began to decline as early as April1942.The Japanese were peculiarly and astonish-

ingly unprepared to convoy and protect theirmerchant marine against attack whether by seaor air. Merchant vessels were not armed at theoutset and guns were not available to arm morethan a portion of them. Those in the Navy poolwere first equipped, the Army attempted to usefield guns on deck, and dummy wooden gunswere used in some of the civilian fleet as a de-ception. Few vessels were available for convoyservice and many of these were small short-range craft of limited utility. Lacking themeans to convoy, the Japanese neverthelesssent out unprotected vessels in groups and lostheavily as a result. Strenuous efforts were madeto build up the convoying fleet, exposed routes

were consolidated with others that could be bet-ter protected, and finally all important routeswere being operated on the convoy system. Thisof course reduced the carrying capacity of thefleet, for many convoy routes were roundabout,vessels lost time awaiting the formation of con-voys, fast ships were held down to the speedof slower craft, and many a vessel wasted timeawaiting the refueling of short-range escortcraft protecting the convoy. Yet the system wasalways of limited effectiveness because of theshortage of escorts and their lack of proper de-tecting and other equipment. Moreover a moreeffective convoying effort might not have re-duced the vulnerability of merchant shippingto air attack.

Air activity against shipping began to in-crease after our capture of Henderson field onGuadalcanal as the United States effort passedto the offensive and available forces, as well asthe exposure of the enemy, increased. The ship-ping used in the attempted reinforcement ofthe Solomons was largely sunk and the airforces based on New Guinea commenced a.steady attrition of near-by shipping. Submarineactivity expanded and this period of growingeffectiveness of our effort was punctuated bythe smashing carrier aircraft blow at Truk inFebruary 1944, when 186,000 tons of shipping,bottled up by the presence of submarines, weresunk in a two-day raid. By this time the sub-marine force had so greatly expanded that noroute was secure from its attack. No ship wassafe south of Honshu. In the 16 months fromSeptember 1943 to the end of 1944, our sub-marines sent 3,000,000 tons of enemy merchantshipping to the bottom.The three montiis of the Philippine campaign

in late 1944 threw the administration ofthe Japanese merchant marine into confusion.Gradual losses over a prolonged period were ac-centuated and so great was the reduction intonnage by this time that the old methods oforganization and operation became impractical.Carrier aircraft struck heavy blows immedi-ately prior to the Leyte landings and duringthe early Japanese efforts to reinforce the Phil-ippines. Concentrations of submarines aroundLuzon were active and effective. The attemptedreinforcement was frustrated and, in threemonths, the Japanese merchant marine lostmore than 1,300,000 tons of ships, or more


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one-third of its remaining fleet. Notwith-intensified air activity, and particu-

the effective strikes of carrier air, 55 per-of the ship tonnage lost during this periodsunk by submarines.

As 1945 began, the thin remaining life linethe Japanese Empire was a trickle of ships

from Formosa along the South Chinato Indo-China and on to Malaya and theAlthough the effort to run the gauntlet

Allied attacks was great, a few ships gotFor the most part the Japanese were

secure in navigation of the Sea of Japanthe Yellow Sea. As far as possible, inter-and import trade was routed to use thesea haul by shifting as soon as possible

rail. Much of the coastwise traffic was mov-all rail. The railroads were loaded close to

but the decline in domestic inter-islandroughly paralleled the decline in coast-shipping capacity, thus avoiding the over-

of rail lines. On the continent, too,railroads of North China and Korea were

used to shorten ship hauls as much asWithin six months the remaining seawas reduced to chaos.

In mid-January carrier fleets undertook con-sweeps in the South China Sea sink-

10 percent of Japan's remaining merchantIn March came the Okinawa campaignthe discontinuance of further attempts to

convoys between Japan and Singapore.the expected imminent occupation of For-or Okinawa accomplished this objective,

Japan's needs for imports from the southso great that even the huge losses from

submarine and air activity could nother from the attempt to force some ship-through. The occupation of Iwo and Oki-contracted Japan's sea sphere to the Sea

Japan, the Tsushima Straits, and the Yellowwith a tenuous connection to Shanghai andYangtze. March saw also the beginning ofheavy city raids by B-29s which had no sig-

effect upon shipping or upon the rail-though the traflSc upon the latter was

reduced because of the general pa-of industry and commercial activity in

affected cities.Finally on 27 March the highly successful

campaign of the B-29s com-completing the paralysis of shipping.

The Shimonoseki Straits were effectively mined,imposing a virtual blockade upon movementthrough this vital shipping gateway. Eventual-ly all important Japanese and Korean seaportson the Japan Sea and Korean Straits had beenmined. Over 670,000 tons of shipping weresunk or disabled for the duration of the war bymines and the remainder of the fleet was ren-dered largely ineffective. Concurrently everypart of Japan's sea lanes came within reach ofactive land-based aircraft. In July a carrierstrike against Hokkaido and the TsugaruStraits accounted for much tonnage and vir-tually stopped the important movement via therail ferries to Honshu. As early as May sink-ings and serious damages were at the rate of11 percent a month, steel shipbuilding was but30 percent of the peak and falling rapidly, woodshipbuilding was down to 12 percent and fuelavailable for the boats in service was but 10-20percent of former quantities. The repair prob-lem was serious with half a million tons ofdamaged shipping in the yards and much addi-tional damaged tonnage unable to reach re-pair yards because of the mine blockade. ByJuly the disintegration was complete.At the time of surrender Japan had but 1,-

800,000 gross tons of shipping afloat, 1,650,000of which were in the Inner Zone. Only 650,000tons of steel ships were serviceable within theInner Zone, or 12 percent of the fleet withwhich she began the war. These ships had beenconfined almost entirely to the trade betweenHokkaido, Korea, and the Japan Sea ports ofHonshu. Shipbuilding was almost at a stand-still and in August total seaborne traffic in steelships was only 312,000 tons or 7.8 percent ofthe peak movement of October 1942. The Alliedstriking agents responsible for this remarkableresult, and their respective shares in vesselsinkings are illustrated in Figure 1. This chartis not to be interpreted too literally for it issubject to a margin of error arising from in-adequacy of data which may be on the order of5 percent. Moreover, it refers only to sinkingsand in no way measures interdiction nor the in-efficiencies in shipping utilization, for example,where effective land-based patrol forced rerout-ing of convoys and compelled shipping to mov6over more circuitous courses.The economic repercussions of the shipping

shortage began early and became drastic,


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GROSS TONSTHE DESTRUCTION OF THE JAMNCSE MERCHANT MARINEBY VARIOUS ATTACKNG AGENTS

(SHIPS OVER 500 GROSS TONS ONLY)((FIGURES FOR 1945 INCLUDE SHf>S DAMAGED AND PUT OUT OF ACTION FOR THE DURATION))

TOTALS

threatening the very life of the nation. Virtuallyall industry suffered in some degree from theloss of vital imports, many of them early in thewar. Imports of 16 major commodities forwhich data are available fell from 20 millionmetric tons in 1941 to 10 million in 1944 andbut 2.7 million in the first six months of 1945.Figure 2 shows the relationship between ship-ping available in the civilian pool, total freighthandled by these ships and total imports of the16 major commodities. The total value of allimports showed an almost steady decline de-spite the decline in value of the yen in 1943.Iron and steel as an industry basic to all war-time industry enjoyed top priority throughoutmost of the war period. But its dependenceupon imported coal and ore made it vulnerableto the shipping attack, and all efforts to protectit by shortening hauls, stockpiling, and greateruse of domestic coal and ores failed to preventa decline in output after 1943. Thus ingot steeloutput fell from its peak of 700,000 tons in De-

cember 1943 to but 300,000 tons in June 1945when its stocks were largely exhausted and theprospect of further import disappeared.The decline of iron ore imports from other

sources compelled an effort to step up ship-ments down the Yangtze from the Tayeh mines.This movement reached its peak in mid-1943.At about this time the attacks of the Four-teenth AF against river traffic on the upperYangtze, stopping daylight operation of bigships above Nanking, reversed the trend ofYangtze traffic, eliminated within approxi-mately 3 months all the gain which the Japa-nese had secured from this source, and endedany hope of continued substantial imports fromthis source. Thereafter, the continued attacksof Fourteenth AF aircraft, augmented byChina-based B-29s, by bombing and mining inthe river and in the port of Shanghai causedincreasing ship losses ana contributed, togetherwith the general shortage of shipping and theconsequent efforts to develop nearer sources of


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^lAPANESE MERCHANT SHIPPING AVAILABLE FOR CIVILIAN USEAND ITS PERFORMANCE DURING THE WAR

MERCHANT SH{PPING (EXCLUDfNG TANKERS) INSERVICEABLE CONDITION S AVAILABLE FORaVILIAN USE (IN CROSS TONS).

TOTAL GROSS TONNAGE OF ALL SERVICEABLECARGO SHIPS IN THE INNER ZONE AFTEFCONSOLIDATION OF SHIPPING.

@ TOTAL TONNAGE MOVED IN CIVILIAN SHIPS (IN METRIC TONS! TOTAL IMPORTS INTO JAPAN OF 16 MAJOR BULK COMMODITICS COAL, IRON OHC,BAUXITE, STEEL, SCRAP IRON, LEAD, TIN, ZINC, PHOSPHORITE S PHOSPHATE, DOLOMITE,MAGNESITE, SALT, SOVBEAN CAKE, SOYBEANS, RICE S PAODT, OTHER BRAINS ft FLOURS,

AND RAW RUBBER. (M METRIC TONS)

1,000,000

JFMAMJJASONDJFMAMJJASONDJFMAMJJ*1943 1944 1945

Figure 2.


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ore in North China and Korea, to the steady de-cline in importance of the Tayeh oi'e. Access toone of the most significant sources of iron oresupply had been effectively denied.

Although tanker sinkings were insignificantuntil the carrier strike at Truk early in 1944and did not rise consistently above new con-struction until August 1944, oil imports passedtheir peak after August 1943 and behaved er-ratically but moved generally downward, there-after. The advent of the convoy system with itsgreat sacrifice of eflficiency, the loss of Navytankers at Truk, the increasing tanker sinkingsin the fall of 1944, and the gradual constrictionof the route to the East Indies and Malayabrought a fall in oil imports which produced adesperate shortage of the vital fuel. Strenuouseff"orts to force the movement produced peaksof short duration, but after July 1944 the tankertonnage devoted to import declined precipi-tously and by April 1945 the movement ceased.The effect on Japan was immediate. Stocks hadlong since been depleted and consumption wason a hand to mouth basis. Even the oil supplyfor the shipping industry, rated second only toaviation fuel, began to dry up and a consider-able tonnage, particularly of the smaller ves-sels, was laid up for lack of it.

In most of the important industries not onlyquantity but quality had to be sacrificed. Localraw materials, often of astonishingly poor qual-ity, were exploited in the attempt to substitutefor the loss of import capacity. The use of sec-ondary scrap was pushed. Even direct muni-tions suffered in quality when the ferro-alloysbecame well-nigh unobtainable and when alu-minum output had declined 76 percent in asingle year from the virtual stoppage of bauxiteimport.

Finally the nation was sorely pressed forfood. Local production had declined, partlyfrom the loss of manpower and partly from theshortage of imported fertilizers. Fishing de-clined precipitously to less than half its prewarvolume from a variety of causesrequisition offishing vessels by the Navy, the increased haz-ards and reduced areas open to the boats, theshortage of fuel, the shortage of hemp for fish-nets, etc. Never wholly self-sufficient in foodsupplies, Japan, even on a reduced ration, wasstill compelled to import large quantities of thestaple grains. The position became so acute

!c

ie

that in April 1945, it was decided to devotevirtually all of the small remaining shippingcapacity to the import of food and salt, sacrific-ing the trickle of industrial raw materials thathad still been flowing in. In short Japan was, inthe spring of 1945, virtually isolated. The rawmaterials basis of her economy had been cutoff. She could look forward only to gradualstarvation and increasing impotence.Japan still had, however, a functioning rail-

road system which was physically intact. Un-dermaintenance had set in, to be sure, but ithad not yet affected the smooth operation of thesystem and had caused little decline in its peakcapacity. The few scattered attacks upon railfacilities and the great raids upon the citieshad been mere pinpricks as far as the railroadsystem was concerned. A few traffic inter-ruptions of very temporary duration had oc-curred. Line and yard capacity was essentiallyunimpaired. Only the loading, unloading, andcollection and delivery systems in some of thecities subjected to the great fire raids had beendisrupted. But in those locations the need forsuch facilities had contemporaneously declinedas traffic demands fell with the burning of in-dustrial and commercial plant and the exodusof population. The railroads were still capableof serving. Even the atom bomb attacks had buttemporary and minor effects upon railroad fa-cilities and service. Only the carrier strikeagainst the ferries from Hokkaido was a significant blow against the railroad system as afunctioning unit. Interdiction of the railroadsystem, had it been undertaken, would have de-prived Japan of all significant transportationand left the nation industrially and militarilyalmost completely immobile.

CONCLUSIONSThe war against shipping was perhaps the

most decisive single factor in the collapse of theJapanese economy and the logistic support ofJapanese military and naval power. Subma-rines accounted for the majority of vessel sink-ings and the greater part of the reduction intonnage which brought about the collapse ofthe shipping services. Although submarineswere never available in sufficient numbers toenforce a blockade, they were able steadily to;reduce the tonnage afloat and to impose in-


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inefficiencies upon the operation of thetonnage.

The marked effectiveness of the submarinewas due to a variety of favorable

The complete failure of theto anticipate heavy submarine attacks

to guard against them presented an openinviting field for such attacks. Belated ef-to organize a convoy system were poorly

and executed, resulting in the verysacrifice of performance. Technical

equipment was poor. Efforts tomerchant vessels for protection against

were belated and inadequate. Mean-ile, excellent intelligence enabled our sub-

to find targets with increasing successefficiency. Finally the development of ef-

cooperation between the submarines andair arm permitted the results of continualpatrol and search to be translated into ef-

submarine attack, where such attackthe most appropriate method to employ. Itbe understood, however, that particularly

the sea lanes contracted and more effectivewas supplied, the task of the submarinehazardous and losses were considerable.

Early in the war combat vessels were thetarget. Commercial shipping followed

when there was a choice between dry-cargoand tankers, submarines were expected

prefer the tankers. But not until 1944 werespecifically directed to seek out

for destruction. Had submarines con-more effectively in the areas where

were in predominant use after mid-oil imports probably could have been re-sooner and the collapse of the fleet, the

arm, merchant shipping and all other activ-dependent upon oil fuel hastened. With the

required to shift the emphasis of shipbuild-to tankers, Japan could never have caughteven temporarily with the rate of sinkingsmight have been produced by such prefer-And the fuel shortage might have beenat the end of 1943 rather than a year(Appendix A).

Carrier-borne air attacks, when directedlarge concentrations of merchant ship-

were by far the most devastating attacksall. They were, however, sporadic and not

of a continuing program to neutralizeshipping lanes. In general the responsi-

bilities of carrier air were presumed to lie else-where and to relate more directly to naval oper-ations. Even the raid on Truk was designedmore to seek out and destroy naval units thanto sink merchantmen. However, when carrierair went into an area Japanese shipping therewas completely disorganized and outboundmovement virtually ceased for a time. Its rangefrom the carriers was limited, apparently from200 to 300 miles from the take-off point, but itsbases were mobile and the strong carrier taskforces seem to have been able to operate withrelative impunity in the later stages of the war.The concentrations of shipping against whichthey operated so effectively were, of course, inpart produced by the activities of other arms.It is possible that, subject to the limitations im-posed by the threat of Japanese counteractionwith a portion of their fleet and carrier forcesstill intact, carrier air might have been directedearlier and more heavily against Japanese mer-chant shipping. And since shipping was themost important single key to the logistic basisof the Japanese military and naval machine,such a policy should have been enormouslyprofitable. For example, had carrier task forcesbeen able to cruise south of Java and Sumatrain the latter part of 1943, carrier aircraft couldhave caused devastation to Jap shipping in theJava Sea and Singapore areas where large ton-nages, particularly of tankers, were concen-trated. Likewise a heavy blow by carrier airagainst shipping in the Inland Sea during thesummer of 1944 would have netted tremendousresults. Either or both of these raids wouldhave seriously reduced the Japanese merchantfleet and, in consequence, Japan's war-makingpotential.

Land-based aircraft, both Army and Navy,were able to and did undertake extensive andsustained armed search of shipping lanes. Theynot only disposed of tonnage by their ownaction, but provided information of value toother agencies in cooperative endeavors, includ-ing the submarine forces. They were operatingagainst increasingly dispersed and smaller tar-gets. Their contribution to sinkings of large ves-sels was smaller than those of other principals.Army land-based air committed to the inter-

diction of such Japanese shipping as was in-volved in providing logistic support for theperimeter garrison forces was highly effective.


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The destruction of considerable tonnage inRabaul harbor and the successful interdictionof this important port is an outstanding ex-ample. In direct support of our offensive op-erations, enemy shipping along the lines ofadvance, including barges and all types ofsmaller craft, were attacked and destroyed.

Since such operations comprised the predomi-nant employment of Army air against shipping,the principal reason for its failure to sink largernumbers of large ships is apparent. Other mili-tary objectives are said to have precluded theassigning of more than a small effort (1.5 per-cent of combat sorties) to antishipping strikes.It is difficult to avoid a feeling that a full reali-zation of the importance of merchant shippingas a tai-get did not figure adequately in the ap-praisal of relative target priorities. Certainlythe war against shipping would have been ex-pedited had Army land-based air been availablefor steady concentration against this target,but the wisdom of such employment at the ex-pense of other military objectives cannot beassessed by this Division.

Land-based air was generally limited in itscoverage by the range of its aircraft and theposition of its bases in relation to the importanteconomic shipping lanes. Its capabilities stead-ily increased throughout the war and as ourforces advanced through the Philippines towardJapan, land-based air forces brought these vitallanes under increasingly heavy attack. At thecost of increased length of run and vessel turn-around time, the Japanese progressively re-routed their dwindling shipping until it becameimpossible longer to escape the depredations ofair attack.

Considering the entire war, relatively fewlai'ge ships were sunk by land-based aircraftfurther than 600 miles from their bases, but bythe time our forces had undertaken sustainedoffensive action, armed search and strike mis-sions were continuous over doul)le that range.The Japanese upon interrogation generally pro-fessed to discount the menace of land-based airwhen based more than 600 miles distant fromlines of supply, nor did they discontinue ship-ping operations over such routes because of thepresence of land-based air more than 600 milesdistant, although diversions were made wher-ever possible to avoid the closer approach to air.The willingness to commit shipping in the

face of severe losses reflects the desperate needof the Japanese for strategic imports regard-less of cost and the aura of unreality that sur-rounded Japanese shipping planning. As a resultof these desperate measures taken by the Japa-nese, complete interdiction of major shippinglanes was not achieved by the limited land-basedair committed to this objective, although ameasure of interdiction was achieved and profit-able reductions of Japanese shipping resulted.Among the most significant contributions ofArmy air in the strategic war against merchantshipping was the mine-laying campaign con-ducted by the B-29s. Prior to March 1945, mine-laying by aircraft and submarine was limitedand not an important factor in the progress ofthe war except in some local situations. Sink-ings were few and no important blockade effectwas secured except in the Yantze. The B-29mine-laying campaign was, however, a very suc-cessful effort. Four desired effects were accom-plished simultaneously, viz:

(1) The tonnage of merchant shipping inoperating condition was greatly re-duced ;

(2) The use of ports previously protectedfrom submarine blockade was ren-dered decidedly dangerous and theShimonoseki Straits, the most im-portant shipping crossroads in Japan,became virtually impassable;

(3) Access to repair yards was denied tomuch damaged tonnage and all re-pair facilities were congested beyondtheir capacity

(4) The administration of shipping wasthrown into hopeless confusion.

It is believed that this campaign, begun earlierand laid on with greater weight, would have re-duced effective shipping nearly to the vanishing^point. It would thus have produced a conditioniof crisis in Japan sooner than actually occurred.Recognition of its potentialities by the planners;at a much earlier date would have been requiredto establish the necessary priority, to traincrews, and to secure the production and ship-ment of the necessary supply of mines in orderMthat the campaign might have commenced as'isoon as possible after the B-29s were based jwithin range.

Failure to attack the railroad system as soon


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as the foi'ce was available resulted in the lossof a major opportunity. With her shipping soseriously reduced, Japan depended almost en-tirely upon her railroad system for transporta-tion. The disposition and supply of her forcesto resist invasion must rely upon the railroadsthe remaining industry must rely almost whollyupon Japanese sources of fuel and raw materialwhich could be transported only by rail ; and thedistribution of food and elementary necessitiesof life could not be accomplished without therails. The Japanese railroad system was, more-over, one of the most vulnerable of any size tobe found anywhere. With its through movementconfined almost entirely to the two main linesthe length of Honshu, and the supply of bulktraffic to these lines bottlenecked at the Kan-mon tunnel on the south and the Hakodate andAomori ferries in the north, opportunities fordiversion and rerouting were almost nil. More-over the bulk of the traffic had become long-haul with the vii-tual demise of coastwise ship-ping and traffic must use one or another of thesemain lines for a substantial portion of theirlength. Any serious interruption of either lineand especially of the high capacity Sanyo line,west of Kobe, would have seriously reduced themajor flow of traffic from Kyushu northeast tothe industrial cities and the loss of both lineswould have paralyzed the flow. The less impor-tant movement southwest from the northern tipof Honshu could have been similarly paralyzedby the cutting of both lines, for it was largelythrough business. The main line between Tokyoand the Kanmon was particularly open to at-tack because at many points it hugged the coastand its approximate location could be picked upby radar by reference to coastal features evenunder conditions of low visibility. All lines hadmany structures, such as bridges, tunnels, cuts,fills, and retaining walls which would have beendesii-able targets for carrier-borne dive bombersor similar aircraft under visual conditions. TheKanmon tunnels themselves, keys to the mostimportant coal and steel movement, were mostvulnerable. They were easy to pick up by radarand required only destruction of tunnel mouthsand approaches for eff'ective neutralization. TheHonshu rail system, although it used some low-grade Honshu coal, could not be fully workedwithout considerable quantities of Kyushu andHokkaido coal.

A program, therefore, involving the success-ful destruction of the Kanmon and the con-temporary destruction of the rail ferries fromHokkaido (as was actually done quite eff'ec-tively by a carrier task force at a late date)followed by half a dozen well-chosen line cutson the main routes would have disposed effec-tively of the Japanese rail system as an eco-nomic asset. The system had only extremelylimited recuperative powers. Neither plans normaterials were in hand for replacing any majorstructures. Not even bridge timber had beenassembled as a precaution against such attack.And the material required could not be obtainedfrom the mills except after considerable lapseof time. The objective of the program would beto stop the flow over the main routes. Its accom-plishment would require very little physicaldestruction. Recuperation need not worry theattacker, for no quick reaction was possible.Had it begun, however, force was at hand tobring it promptly to an end.

It appears that force was at hand withinrange of the desirable targets by mid-April1945. Reconnaissance could have been securedduring the previous months. One hundred dis-patched sorties by B-29s with 800 tons of Azonbombs should have been sufficient for a completeprogram of line cuts, including the approachesto the Kanmon tunnel, designed to cut all sig-nificant main rail routes. The program wouldrequire also the cooperation of a carrier raidagainst the Hokkaido ferries of similar magni-tude and effectiveness to the one actually em-ployed, but it would have been preferable toaccomplish it at an earlier date. Alternativelythis operation against Japanese rail lines couldhave been accomplished with 650 B-29 sortiescarrying 5,200 tons of ordinary genei'al-purposebombs or 1,740 carrier-based sorties carrying1,300 tons. A combination of the two types ofattack might prove to be the most efficient. Asimilar or somewhat greater eff'ort monthlymight have been required to maintain the inter-diction. Figure 3 indicates a possible plan ofareas within which the necessary cuts mighthave been spotted and the order of importanceof the several zones. It also spots the points in-cluded in calculating these force requirements.A table of force requirements (Figure 4) fol-lows the map.

Such a decimation of the rail system could10


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seriously impeded military dispositions es-for defense against invasion. It could

paralyzed all economic traffic by rail, notby cutting the main routes, but also by

the separated segments of the coaleven for local operations. Even the lowfuel available on Honshu could not have

distributed where needed, and stocks inhands of most divisions of the railroad werefor but a few days operation. The res-

of the railroads would have become thetask of the day, but would have been

and confused because of the complete lackpreparation to cope with such a situation.

Japan would have been paralyzedmight have been ripe for surrender soonerwas actually the case. It is difficult to real-

the profound and ramifying effects of acomplete transportation tie-up. Such a

interruption of transport has not oc-in the modern world. Judgment, there-

differs as to the significance of the effectswould have been produced upon the peo-

and upon the government and the rapiditywhich such effects would have been felt.

Had an invasion still appeared necessary, andhad some local railroad operation been restoredfor military purposes, the air foi'ces availablecould have plastered the entire limited rail sys-tem during the several weeks immediately be-fore the landings.The employment of forces against oil targets

in accordance with the effective plan was largelya duplication, from the economic point of view,of results already assured by the success of theshipping attack. The urban area attacks, whileduplicated in the same sense, accelerated theeconomic decline and produced morale and polit-ical repercussions of a type which would havebeen secured more slowly by the continuingstrangulation of shipping. The weakest pointirt Japan's economic structure and the one whichwas already most nearly disposed of was hertransportation. A combination of accelerated andintensified assault against shipping by thenaval and air arms, coupled with the type ofrailroad attack discussed above, should havebeen ample to complete the destruction of thenation's war-making potential.

Figure 4.Force requirementsB-29 and carrier-based A/CTargetNotype


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been ample to complete the destruction of thenation's wai'-making potential.

It is possible that the social and political ef-fects of the transportation attack would havebeen as effective in forcing a Japanese sur-render as were the methods actually employed.But this is a matter of conjecture. In any eventit appears that the railroad attacks could havebeen well complemented by the city raids andthat both types of attack were operationally

feasible. The two types of effort conducted to-gether might well have advanced the date ofsurrender.Our failure to adopt such a plan appears to

have been due to a faulty assessment of theJapanese position, a failure to realize the fulleffects that had been secured by the massacreof shipping, and failure to recognize the vul-nerability of the rail system or the effectivenessof its neutralization in paralyzing the Japaneseeconomy and military potential.

12


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CHAPTER IITRANSPORTATION IN THE PEACETIME

ECONOMY OF JAPANImportance of Overseas ShipmentsFew countries in the world are more depend-

ent on shipping than Japan. The simple factthat she is an island community where local de-mands far exceed local production, implies con-inuous overseas shipment for the maintenance

of her economic life. In addition the multipleisland character of the country requires thatost of the domestic trade be waterborne. De-endence on the outside world is accentuatedy the extremely limited productivity of theand and the unbalanced ratio existing betweenresources and population.The area of the islands comprising Japan

roper is 147,611 square miles. Fully 85 per-ent, however, is in rugged forested mountains

is relatively unproductive. In natural re-Japan is the poorest of the great pow-

In the products of forests and of the sea,has perhaps adequate resources for a

economy, but in most of the agricul-animal, and mineral products there areshortages.

Before the war Japan normally depended on(including those from the colonies) for

percent of her total food supply on the basiscaloric intake. Almost all of the sugar, and

than half of the salt, soy beans, and cornfrom overseas. In addition, it was neces-

ary to ship in enormous quantities of rice(about 20 percent of the total consumption)large percentages of the wheat and milletequirements.A relatively high degree of industrializationdded to the demand for overseas products. Ap-roximately one-third of the raw materials ofindustry were imported. Included in this cate-gory were 100 percent of the cotton, wool,rubber, phosphorite, sodium nitrate, potash,bauxite and magnesite needs. In addition, overhalf of the iron ore, coking coal, ferro-alloys,scrap iron, petroleum, pulp, oils and fats, hidesand skins, industrial salt, lead, tin, jute and

hemp requirements represented inward ship-ments. Substantial quantities of the paper, lum-ber, coal, soda ash, ammonium sulphate, pigiron, copper and zinc requirements were alsoimported (Figure 5).Although shipping space for large quantities

is not involved, the further dependence of in-dustrial Japan on overseas materials is illus-trated by her almost complete dependence onforeign sources for such essentials as anti-mony, nickel, quicksilver, mica, asbestos, shel-lac and resin, quinine, and tanning materials.In fact complete self-sufficiency in the raw ma-terials of industry is found only in raw silk,sulphur, fish oil, and a few minor products.

Likewise important was the dependence onoverseas export trade in Japan's peacetimeeconomy, although the manufactured exportgoods were far less demanding on shippingspace than the bulky incoming raw materials ofindustry. Many of the exports, however, repre-sented reshipment of imported materials. Thiswas true of the largest single export, cottongoods, and many of the lesser ones, such asflour, refined sugar, rubber goods, metal manu-factures, paper and rayon. Of the major ex-ports, only silk and pottery were manufacturedfrom domestic raw materials and had not re-quired water transportation at some period intheir production.

Figure 5.Sources of raw materials, 1937(percent 'of total)Product


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Japan's foreign trade figures normally loomlarge among those of the world. Imports andexports have shown a general upward trendsince the country was opened to foreign com-merce in 1854. By 1937 the total trade hadreached 6,958,596,000 yen (about $2,000,000,-000), an all-time high up to that year and afigure that has since been exceeded only in 1940(Figures 6 and 7). This total gave Japan sixthplace in world exports and fifth place in im-ports for the year. Imports accounted for3,783,177,000 and exports for 3,175,418,000 ofthe total leaving an excess of imports over ex-ports of 607,759,000 yen. This slightly unfavor-able trade balance was the usual situation inJapanese foreign trade until 1938.

Figure 6.Foreign trade of Japan1900-43(In 1,000 yen)

Year


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Netherlands Indies (Figure 11).In contrast to the raw-material nature of

most of Japan's imports, exports consistedlargely of manufactured and semi - finishedgoods. Outstanding were the textile and cloth-ing products, with some metal manufactures,processed foods, pottery, glassware, toys, andwood products. Occupying first place in valuewere cotton piece goods, followed by raw silk,these two leading items accounting for 32.5 per-cent of the annual value of exports (Figure12).

Figure 9.Japanese import trade, 1936COMMODITIES

Figure 10.Sources of Japanese foreign imports,1929 and 1936

Product


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Figure 12.Japan's export trade, 1936COMMODITIES


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Figure 14.Source.? of Japanese receipts from overseas(including colonial)

Area


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By far the most important item was coalcarried from Kyushu to Honshu and from Hok-kaido to Honshu (Figures 51 and 52). Fromnorthern Kyushu ports it flowed eastward toInland Sea ports, principally Osaka, and to Na-goya, Shimizu and Tokyo Bay ports. Hokkaidocoal was shipped from Hakodate, Muroran, andKushiro to Tokyo Bay ports, and from Otaruand Rumoe to the Japan Sea ports of Honshu,principally Fushiki. Significant amounts of cok-ing coal from Karafuto were shipped to Hok-kaido and Honshu.

Karafuto was the source of other bulk prod-ucts, principally fish meal, pulp, and paper,that were shipped south to Honshu. Hokkaidoports shipped, in addition to coal, large amountsof paper, pulp, lumber, metal products andfoodstuffs, nearly all destined for Honshu ports.Specific items included steel ingots, lead andzinc, copper, manganese and chromite ores, andsulphur. Hokkaido was the principal Japanesesource of wheat, beet sugar, and dairy products.Large quantities of beans, about 1,000,000 tonsof potatoes, and several hundred tons of freshand canned fish products were also shippedeach year.

Shikoku's contributions to domestic trade in-cluded cereals, salt, non-ferrous metals, espe-cially copper, ferrous concentrates, fertilizer,and limestone. Kyushu, in addition to coal,shipped pig iron, rolled steel products, coke,cement, refined metals, chemical products, soda,and cereals. Okinawa was the source of all thecane sugar produced in Japan proper, most ofwhich was shipped north to the main islands.

Originating on Honshu and shipped largelyintra-island, were coal, soda, and fertilizershipped to Ube, cereals from Japan Sea portsto west coast population centers, oil from Ni-gata and Funakawa to east coast industrialcenters, iron and steel from Hirohata and Ka-maishi and limestone from Yoshizu.

Although many ports were involved in thehandling of the foreign and domestic trade de-scribed above, the bulk of it passed throughrelatively few. Of the 44 open ports in Japanproper and Karafuto, 18 were comparativelyimportant in foreign trade. And of these, Kobe,Yokohama, and Osaka handled 82.8 percent ofthe total foreign trade of 1937 (Figure 16).The coastwise trade was more widely distrib-uted, but Osaka and Tokyo were outstanding in

volume handled.Inland waterway traflSc was negligible, being

confined almost entirely to the networks ofriver channels and canals found in the deltacities, principally Tokyo and Osaka. Here bargesand sampans performed a delivery service.Transition to a War Economy: Changes in thePattern of Imports

The demands of the China war and the prep-aration for more serious war necessarily re-sulted in a change in the character of Japan'soverseas trade, gradual at first, but rapid inlater years. On the import side there was lessemphasis on non-essential foods, luxury items,textile raw materials, and other items for homeconsumption and export. Imports of raw cot-ton, wool, pulp, and wheat in 1940 were onlyone half as great as those in 1936. There weresimilar declines in the imports of other rawmaterials, a large part of which was normallyprocessed in Japan and reshipped overseas.Corresponding declines in the exports of thesecommodities were apparent after the depletionof stockpiles.

Off'setting these declines were increased de-mands for machinery, especially machine tools,motor vehicles, bearings, ores and metals, andpetroleum. Gearing for war meant that theiron and steel industry, when confronted withthe huge demands of shipbuilding, production

18

of artillery, armored vehicles, aircraft, ammu- |


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aircraft manufacture and in flares and incendi-aries, both required large amounts of importedraw materials. Salt, in addition to its uses as afood and as a food preservative, was the basisfor many chemicals which in turn were es-sential for the rapidly expanding industries ofpetroleum refining, aluminum production, andthe manufacture of explosives. The domesticpetroleum industry was able to fill only one-tenth of the needs for aviation gasoline, fuel oilfor the imperial fleet, and motor gasoline andlubricants essential for motorized warfare.

These increases in demands for overseasproducts met a succession of restrictions ofsource areas beginning with the outbreak ofthe European war in 1939. This event alonemeant the loss of most German products andmany of those originating in other belligerentcountries. In 1940 the United States and coun-tries engaged in the European war imposedexport embargoes on many commodities neededin Japan. Among the more serious losses ex-perienced were petroleum from the UnitedStates, copper from the United States, pig ironfrom the United States and India, scrap ironfrom the United States, non-ferrous metalsfrom Canada and rubber from British Malaya.Japan's import trade changed accordingly.

In July 1941 Japanese credits were frozen inAmerican, British, French and Dutch areas re-sulting in the further loss of important com-modities including United States cotton, lumberand pulp, Australian wool and iron ore, Cana-dian lumber and pulp, Malayan iron ore andIndo-Chinese coal.The declaration of war on the United Nations

meant the virtual restriction of Japan's foreigntrade area to Northeastern Asia, a situationenduring, however, only until the conquest ofareas to the south. In possible anticipation ofsuch a contingency, every effort had been madeto increase the productivity and versatility ofthis area. As early as the spring of 1939, Japanannounced a plan of becoming self-sufficientwithin the "yen bloc" by 1942 in iron and steel,light metals, zinc, coal, soda, sulphate of am-monia and pulp.Self-Sufficiency Through the "Co-Prosperity Sphere"

During the conquest and occupation of thesouthern ai'ea, plans for economic self-suf-ficiency within the Greater East Asia Co-Pros-

perity Sphere commanded much attention. TheCo-Prosperity Sphere was considered to includeJapan, Manchukuo, China, French Indo-Chinaand Siam, the countries within the sphere inearly 1942. In addition, the Netherlands EastIndies, the Philippines, Malaya, and Hong Kongwere countries "expected to participate in thesphere." On the basis of average trade figuresfor the period 1935-37, only 30 percent of theexport trade of the 8 countries, was confined tothe sphere, the remaining 70 percent beingdestined for third countries. About 39 per-cent of the imports of the 8 countries originatedin the sphere, 61 percent arriving from thirdcountries.

It was considered easily possible to attainself-sufficiency in food-stuffs. Rice, the princi-pal commodity, was produced with a slightsurplus. There were still greater degrees ofself-suflficiency in beans, sugar and many mis-cellaneous foodstuff's. Of the principal com-modities, only wheat showed a deficiency(Figure 17).Figure 17.Self-sufficiency rate of selected commodities

in Greater East Asia Co-Prosperity Sphere'(Based on average conditions 19.S5-37)

Commodity


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In the important metallurgical industriesthere was an adequate supply of iron ore andcoal but a shortage of pig iron, scrap iron andsteel requiring annual importation from thirdcountries of 660,000 metric tons of pig, 630,000metric tons of scrap, and 660,000 metric tonsof steel. The aluminum industry was in a situa-tion similar to that of the iron and steel in-dustry with an ample supply of raw materials,but with need for expanding refining facilities.There was self-sufficiency in tungsten, anti-mony and magnesite. Annual production of tinwas 13 times greater than the requirement,but the ratio of self-sufficiency in copper, lead,zinc and nickel was very low.

Petroleum supplies within the sphere werenot as abundant as coal, and self-sufficiency inmineral oils was dependent on increased pro-duction in the Netherlands East Indies and inthe Japanese synthetic industry.

In summary, the evaluation of potential self-sufficiency in the Co-Prosperity Sphere con-cluded that there would be little to worry aboutin foodstuffs, difficulty in meeting fibre andnon-ferrous metal requirements, and serious

problems in disposing of certain agriculturalsurpluses, namely rubber, beans and sugar.

Conquest of Southeastern Asia and the EastIndies gave Japan control of the bulk of theworld's supplies of rubber, tin, antimony, juteand quinine, as well as vast supplies of pe-troleum, iron ore, coal, phosphorite, bauxite,sugar, corn, and rice. This storehouse of rawmaterials, supplementing the materials andmanufacturing capacity of the Inner Zone, gaveJapan a position of strength in the waging ofwar as long as sea transport to the south re-mained unmolested.

During that period Japan drew heavily onthis area for bulk raw materials and manycritical items required in smaller quantities.The general order of priority was as follows:rice, bauxite, rubber, iron ore, tin, lead, tan-bark, turpentine, resin, cowhide. On the basisof tonnage the principal commodities were pe-troleum from the Netherlands Indies, bauxitefrom Malaya and the Netherlands Indies, ricefrom Indo-China and Siam, iron ore from Ma-laya and the Philippines, and coal from Indo-China (Figure 18).


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Figure 18 (2) .Japavese imports of iron ore, lff.',0-/,5


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Figure 18 (5) .Japanese imports of scrap iron, 191,0-45


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Figure 18 (8) .Japanese imports of zinc, 19i0-i5


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Figure 18 (11) .Japanese imports of salt, 1940-i5


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F'IGI'RE 18 (14) .Japnneae imports of rice ami paddy, }/,{)n-/,.'>


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CHAPTER IIIPREWAR TRANSPORTATION FACILITIES

History of the Merchant FleetJapan was historically a maritime nation,

but during the two centuries prior to the ar-rival of Commodore Perry the isolationism ofthe Shoguns had stifled ocean navigation. Itwas not until the Meiji Restoration after themiddle of the nineteenth century that Japantook part in world trade. Her first efforts toacquire a merchant marine were guided by foi'-eign experts. Progress was slow. By 1870 Japanhad a merchant marine of only 25,000 tons.i Inthe ensuing 40 years Japan's rapid progressfrom maritime infancy to sixth place amongthe maritime powers of the woi-ld with a mer-chant fleet of 1,100,000 tons, carrying 40 per-cent of her own trade in her own bottoms, wasa history of the dependence of Japanese im-perial ambitions on shipping (Figure 19).The conquest of Formosa in 1874, the Sino-

Japanese war in 1894, and the Russo-Japanesewar in 1904, each in its time, gave the Japaneseshipping industry a tremendous boost, as, likeall nations, Japan learned that in war she mustdepend on her own merchant shipping, and con-versely must have merchant shipping as a pre-requisite to war.The world shipping slump preceding WorldWar I reduced the natural demand for Japa-

nese shipping, but by this time the Japanesegovernment had learned its lesson and begana program of fostering the merchant marinewhich continued until the recent war. In 1909 a

(') Many vessels were used in fishins and inter-island tradein Japan before the Restoration, but they were not "European-style" ships. These small vessels were a Japanese variety of theOriental junk and were built of wood. As new steel ships were built,after the European manner, they were called "kisen", literally"steam vessel". Later on, with the advent of the internal combus-tion enffine. the older, wooden. Japanese-style vessels bepan to beequipped with power, and were called "kihansen", literally "poweredsailing vessel". In mole recent years, the sa'l was not always pro-vided, but the term "kihansen" was retained to distineuish these"Japanese-style" vessels, usually but not always built of wood, andseldom exceedinK 250 cross tons burden, from the more modern"European-style" kisen, usually but not always built of steel, some-times as small as 50 tons, but usually over 500 tons. At the sametime the term "kisen." oriRinally meaninpr steamship only, came toinclude all "European-style" shiris. whether projielled by steam orDiesel. This unique Japanese distinction is preserved herein by usingthe words "kisen" and "kihansen" to distinguish between steel.European-style ships and wooden Japanese-style ships wherever con-fusion mfirht exist. The word "ships", when used alone, refers tokisen of over 500 pross tons.Gross tonnace is a measure of a ship's size, and is calculated as thenumber of hundred-cubic-foot units of space covered by the maindeck. Wherever not otherwise specified herein, tonnages piven aregross tonnages.

selective subsidy program designed to increasethe number of new and larger ships in worldtrade was inaugurated.Figure 19.History of the Japanese Merchant Marine

( In gross tons as registered in Japan and the Japanese Empire)

Year


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As a result of mergers NYK becameof the world's greatest shipping companies.1980 the size of the fleet crested at 4,300,000and thereafter receded slightly under the

of the world depression. During 19311932 the stress of world events produced

ofound changes in Japanese shipping poli-Political repercussions of the Manchuria

the uncertainty of world trade, theembargo, and fluctuations in foreign ex-

culminated in the depreciation of thelong steady at 49- cents, to 29 cents inAs freights were paid in foreign currency,

shipping gained tremendously; forsame reason, Japanese exports increased 75

by volume. In this favorable marketJapanese merchant marine, shocked into a

recession in 1931, began the upturn1933.New government subsidies designed to en-the scrapping of old ships and the

of fast new motorships greatly im-the quality and carrying capacity of the

fleet in the succeeding years, althoughgross tonnage did not increase much (Fig-20). With the great need for shipping re-

from the ambitious industrial programManchuria, Japan was able to keep her own

busy and had to rely on foreign ships forcarriage of nearly half of her foreign trade.

of the RailroadRailway construction in Japan was initiatedthe year 1869 when the Japanese govern-

proposed construction of a trunk line be-Tokyo and Kobe with branches to

and Tsuruga, a Japanese seaportof Kyoto.

Since the state treasury was unable to financeproposed construction, an English offer to

the required funds was accepted, and a20. Annual construction of fojir main cate-gories of steel merchant ships in Japaneseshipyards, 1931-41(In gross tons)

Year


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lines. Numerous tunnels, bridges, retainingwalls, and steep grades are necessary.Through railway traffic was carried on be-

tween the Japanese home islands of Hokkaidoand Honshu and Kyushu and Honshu via rail-road ferry. Each of the four main industrialai-eas of Tokyo, Nagoya, Osaka-Kobe-Kyoto,and Moji-Shimonoseki has an exti-emely welldeveloped railway net within its immediate en-virons. Beyond these urban areas however, therailway facilities rapidly decline to two, or atmost three, trunk lines connecting these mainmanufacturing centers with each other andtheir principal sources of supply (Figure 21).Most of the railroads in Japan are single-

tracked and steam operated. The notable ex-ception to this is the Tbkaido main line and itsextension to Shimonoseki, the Sanyo main line.This entire route is double tracked and the sec-tions between Tokyo and Numazu, a distance of78 miles, and between Kyoto and Akashi (whichis west of Kobe), a distance of 52 miles, areelectrified. While it may seem a paradox thatthere is such emphasis on steam power, in acountry so abundantly supplied with hydroelec-tric power, it must be understood that theArmy in Japap had not permitted extensiveelectrification of the railway system out of fearof increasing the vulnerability of the system toattacks and breakdowns.Normal Rail TrafficThe Japanese railroads before the war car-

ried about one-third of tlie tonnage of the coun-try's domestic trade. As described above, thegeogi-aphical situation tended to encouragewater transport at the expense of the develop-

ment of land transport. As a result Japan'srailroads were unique among the systems ofthe world for their dependence on passengertraffic. Revenue from passenger traffic and pas-senger train mileage consistently exceededrevenue from freight and freight train mileage.

Freight consisted predominantly of bulk rawmaterials carried largely on short hauls.Freight arrived in the larger ports by vesseland was moved by rail to industries located inthe interior. None of the traffic required longhauls by rail. Railroad facilities were concen-trated in the large ports, and industries locateda distance from the ports were fed by short railhauls from the docks, storage yards, and ware-houses, contiguous to the unloading piers. Agri-cultural and forest products of the interior wererail-hauled short distances to the nearby coastalports. Mineral products constituted about one-half of the total tonnage; coal alone about 38percent. The 19 items listed in Figure 22 in-clude about three-fourtlis of the tonnage. Theprincipal commodities fall into the followingclasses

(1) Local raw materials transported fromproduction areas to consuming or processingcenters: coal, metal ores, limestone, pulp, lum-bei-, charcoal, and firewood. This class repre-sents by far the largest share of materialscarried by rail.

(2) Imported materials transported to con-suming areas: mineral fertilizers and coal.

(3) Foodstuff's: agricultural products of theinterior transported to coastal citiesrice,other grains, potatoes and soybeans, and fishfrom seaports to interior consuming centers.


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GRAND DIVISIONS OF THE JAPANESE IMPERIAL RAILROADS

FIGURE 21711066 O - 47 (Face p. 28)


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741066 O - 47 (Face p. 29)


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(4) Finished i-oducts transported from in-dustrial centers to consuming areas: cement,iron and steel, and synthetic fertilizers.

Freight traffic was most dense in the Na-and Osaka divisions. The total freight car-

ied in 1936 and 1937 amounted to 89,342,111probably a little more than one-half the

domestic trade tonnage for theFreight ton-kilometers for the same

reached 15,656,579,602.Transportation and Roads

The Japanese highway system is primitive. Of900,000 kilometers of roads of all kinds,about 9,000 kilometers are classed as

national highways." These are almostunsurfaced. A party of Survey per-

traveling one of these typical "nationalacross Honshu to Niigata by jeep,

12 hours to cover one 77-mile stretch.or paved roads are concentrated

around the industrial centers of Honshuthe northern tip of Kyushu. Except in the

and Kobe-Osaka areas thereno inter-city trunk highways (Figure 23).

Trucking operations in Japan were almostshort haul operations. Bus traffic

over short distances only. In 1940 there60,000 trucks and 23,000 buses, of wliich37,000 and 14,000, respectively, were op-The motor division of the Imperial

panese Railways confined its work to pickupdelivery of railroad freight.Effect of the Chinese War

The outbreak of the "China Incident" in 1937the Japanese merchant marine a flourish-

industry, busily engaged simultaneously inthe home island commerce necessary

tlie development of the industrial machine,the materials necessary to the devel-of a new industrial growth in Man-and also participating heavily in all

of world trade in all five oceans. In 1937carried 54 percent of her foreign trade

her own ships.Almost immediately a shipping shortage de-

as a result of tonnage requisitioned byArmy for their Chinese operations. Theof shortage varied from time to time in

ensuing years, but the supply of shippingto Japanese for military and civilian

purposes never again equaled the demand. In1937 a very far-reaching piece of legislationwas enacted: the emergency shipping controllaw, the first step in government control ofshipping. While this legislation gave the Minis-try of Transportation absolute authority overall phases of shipping (ship transfers, prices,construction, routes, freight, and charter rates)this authority was not strongly exercised atfirst. A committee of shipowners for "voluntaryjoint action" for the benefit of the industrywas set up under the Ministry of Transporta-tion. The initial regulatory action was entirelyin the form of consultation and cooperation toforestall direct government control. Construc-tion was increased to about a third of a milliontons a year.An immediate effect of the "China Incident"

was the increased need for ships for "near-sea"transportation, as contrasted with the increas-ing pre-occupation in preceding years withships for world trade. The "near-sea" fleet wasincreased during the first few years of theChinese war from two million to three and one-half million tons, one-half million tons beingtaken off world routes and the remaining onemillion tons coming from the shipways of thebooming Japanese shipyards. Purchase of for-eign sliips was encouraged. Many ships werechartered abroad. The average amount of for-eign sliipping under charter to Japanese opera-tors increased from 390,000 tons in 1937 to5.50,000 early in 1941. In spite of all theseefforts, the shipping shortage remained acuteand freight and charter rates rose irresistibly.Succeeding committees fixed and constantly re-vised standard freight and charter rates. By1938, 85 years after the arrival of CommodorePerry, Japan stood next to Britain and theUnited States as the third maritime power inthe world.By 1939 the developments of the Chinese

war resulted in the consolidation of all the var-ious Japanese coastal operations in China intoone company, the Toa Company. The increasingneed for medium and small ships for "near-sea"service resulted in a new subsidy policy foster-ing the construction of small ships under 5,000tons for servicing the expanding Japanese mili-tary and industrial activity on the continent.The intense shipping activity in Japan in thisperiod is clearly illustrated by the fact that at

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the end of 1938 only three-tenths of one per-cent of Japan's merchant fleet was laid up ascompared with 3 percent for Britain and 10percent for the United States. In 1939 Japancarried 60 percent of her foreign trade in herown ships. At this time, in order to stimulateship production and reduce construction costs,a set of standard ship designs was adopted forseveral sizes ranging from 500 to 6,500 tons.New and ever more favorable shipbuilding sub-sidy laws and government financing projectswere instituted.The effect on the Japanese railroads of the

war in China was mainly felt in the great ex-pansion of the industrial economy of the Japa-nese home islands with the consequent increasein production. This expansion was reflected inincreasing activity on the railroads without anycorresponding increase in physical plant ortrack mileage. From 1936 to 1941 freight ton-nage increased 55 percent ; freight ton-miles 83percent; average length of haul 18 percent (to122.8 miles). Meanwhile, partly because ofheavy military movements, passengers carriedincreased 105 percent, and passenger-miles 111percent. Total locomotives increased from4,142 to 5,106, freight cars from 75,000 to 100,-000 and passenger cars from 9,500 to 11,000.The Japanese had long recognized the need

for a long-term expansion of their rail systeman expansion which would keep pace withtheir country's general economic development.A part of this plan was the construction of theKanmon tunnel beneath the ShimonosekiStraits, plans for a standard-guage railroadfrom Tokyo to Shimonoseki, and the construc-tion of a tunnel beneath Tsugaru Strait whichwould connect Hokkaido and Honshu, as well asa number of line extensions and the double-tracking of certain existing lines. The Japanesedid not, however, expect the rapid increase infreight developing during the war in China.The freight load they had expected in the dis-tant future was upon them in a few months.War in EuropeThe outbreak of World War II again removed

the bulk of foreign shipping from the Japanesesphere, and Japan again experienced a near-monopoly of Far Eastern markets. In threemonths the total ship tonnage of all nations inFar Eastern waters dropped from 4,500,000

tons to 3,200,000, the remainder being almostentirely Japanese. In the spring of 1940 theGerman invasion of Denmark and Norway re-sulted in the removal by Britain of almost allthe few remaining Scandinavian ships in theFar East. The urgent need for shipping in homewaters to service the home islands, supply thewar in China, and bring in strategic materialsfrom Southeast Asia and the Indies broughtabout a tremendous curtailment of Japan's"transoceanic" services. The radical clianges inthe disposition of her merchant mai'ine are hereillustrated

GROSS TONS OF SHIPPING


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ship construction, which had been on aupgrade since 1936, was considerably

by priorities given to naval building200,000 tons were built in 1941.

The stiffening attitude of the United States,evident in more and more embargoes

scrap, steel and war implements, encouragedNetherlands Indies to resist Japanese de-

and negotiations similar to those pre-the virtual annexation of Indo-Chinadown in June. Simultaneously, partly be-of the fear of the effects of ship control

pending in the United States Con-but mainly on account of the shipping

for "near-sea" operations, the Japa-began canceling their few remaining for-sailings and recalling the few ships theyabroad. The shortage was so acute that the

ordered all routing maintenancerepair of ships deferred as long as possiblenot performed during the busy summer

In June the Army and Navy requisi-80,000 tons of merchant shipping.

On 26 July 1941, the United States, followedthe British Empire and the Dutch colonies,

all Japanese assets in their countries, andJapanese trade outside their own sphere

to an end. No more oil, copper, iron, steel,aluminum were imported into Japan. Theof foreign vessels fell off greatly,foreign vessels virtually ceased calling at

ports.During the five months before Pearl Harbor

preparations of the Army and Navy en-the requisitioning of great tonnages of

ships. The approximate disposition ofJapanese merchant fleet during 1941 was as

(in thousands of gross registered tons) :


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Figure 2A.~Japanese


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shipping departments of the two services,performing primarily a military function.carried troops and weapons in the occu-of the conquered areas; they supplied

troops in the field and moved them fromto base as the campaigns developed, re-

to Japan when necessary for rein-rcements, food and supplies. Sometimes, in

case of ships returning from importantbases such as Singapore, which happenedto be an important source of industrial raw

these ships brought back civilian im-More often, especially in the case of ships

from purely military ports such asand Rabaul, the ships of the Army and

Navy returned empty to Japan in their greathurry for more troops or supplies. Thus devel-oped the paradox of a maritime nation, desper-ately short of ships, waging a far-flung waracross the seas, but still permitting a conditionto exist where empty ships might frequentlypass each other going in opposite directions.The stage was set for a crippling attack by theAllied forces against the weakest link in theJapanese organization for war: her merchantmarine.

The outbreak of the war with the UnitedStates had no immediate effect on the traffic ofthe Japanese railroads.

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CHAPTER IVTHE ATTACK ON TRANSPORTATION

Shipping attacks during the war in the Pa-cific were executed by a variety of agents andmethods. The weight of attack laid on is shownin Appendix E. The early prominence of thesubmai-ine, operating from distant bases intothe heart of enemy territory is apparent, as isits continued prominence as a major strikingagent against shipping. All of the air forcesthat operated in the general Pacific theatershared to a greater or less degree in the all-outover-all attack on the enemy's ability to trans-port men and material by sea. A great varietyof aircraft was applied to this task, and everysingle plane in operation was potentially con-cerned in it ; any aircraft, armed or unarmed,regardless of the mission at hand, could at leastobserve and report the presence of a Japaneseship, or one that was suspected of being Japa-nese. It should be emphasized, however, thatthe controlling motive in the attention of air toJapanese merchant shipping was the tacticalobjective of interfering with the enemy's mili-tary logistics rather than the strategic objec-tive of reducing his war-making potential athome. Hence the proportion of effort devotedby air to the destruction of large vessels wasnever great, whereas the submarine effort hadas a major objective the disposal of Jap mer-chant tonnage wherever it could be found. It isperhaps debatable whether a sharper realiza-tion of the importance of reducing merchanttonnage would not have suggested a more in-tense and specialized employment of air againstit, but it is diflScult to appraise the availabilityof air for this purpose in the face of currenttactical requirements of seemingly prior localimportance.Some units of our air power were wholly con-

cerned with the detection and attack of enemyships, some made occasional all-out plannedattacks on such concentrations as were reportedin hostile harbors, near or distant ; some scouredthe areas adjacent to points of invasion forlimited periods prior to and during landings;some either periodically or constantly concen-trated on the isolation of by-passed enemy areas,

even to the extent of attacking surface craft assmall as canoes. More closely examined, themethods of attack varied further, from thehigh-altitude bombing of harbors by heavybombers to the glide and dive-bombing tacticsof marine and carrier aircraft ; the skip bomb-ing and masthead-height attacks by low-alti-tude bombers; the night radar rocket attacksby mediums; the strafing, bombing and drop-ping of gasoline tanks by fighters ; the strafingof river barges and launches, the mining ofenemy waters.The agents concerned were aircraft of prac-

tically all the friendly units from India to Aus-tralia to Fiji to Hawaii to Alaska to China.Some of these agents, such as the fleet airwings, had enemy shipping as the top prioritytarget and objective constantly; others had itonly periodically.However, it can generally be stated that

all aircraft capable of being effective in anyway against enemy shipping had it as theirhighest priority as a target of opportunity,other commitments peiTnitting.Submarine action against shipping com-menced immediately after Pearl Harbor. UnitedStates submarines in the southwest Pacific im-mediately engaged in resisting Japan's south-ward advance; the majority of the central Pa-cific submarines moved quickly to the focalshipping lanes off the eastern and southerncoasts of Japan. Despite the limited force ini-tially disposable, results were at once achievedwhich developed gradually into a major

threatof Japanese merchant shipping. The submarinealone, in the early stages of the war, was ableto reach major lanes of economic shipping andstrike them effectively.Spheres of Action

The spheres of action of the various airforces and their roles of action against enemyshipping can, in general, be set forth simply(Figure 26).Northern Pacific.-In the northern Pacific a

small air force composed of the Eleventh AF34


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741066 O- 47 (Face p. 34)


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Fleet Air Wing 4 operated from tiie Aleu-southwestward toward the Japanese main-Their main antishipping actions were con-and extending search down tiie Kurileand medium bomber shipping sweeps in

Sti-aits.Ccnti-al PacificIn the central Pacific the

AF, Fleet Air Wing 2 and marine avia-units operated progressively tlirough the

Ellice, Gilbert and Marshall Islands toPalau group and the Marianas. The Seventh

went on to Okinawa and operatedJapan. In the fall of 1944, B-29 units

the Twentieth AF were deployed in the Mari-and operated in this theater for the re-

of the war. The main shipping actionthe central Pacific force in its course west-

was extended search in the direction ofnew landings, constant attempt at iso-of by-passed areas in the Gilberts andand efforts to neutralize Jai^anese

centers in the Marshalls, Carolines,and Volcanoes.

South and Southwest Pacific.In the souththe Thirteenth AF went the long road

Guadalcanal to the Philippines by way ofSolomons, the Admiralties, northwest New

and Morotai. Fleet Air Wing 1 operatedthe south Pacific area until mid-1944; then,

reforming, it went to the Marianas. TheAF and Fleet Air Wings 10 and 17, allin Australia, were met by the Thir-

in northwest New Guinea and Morotaiswinging a dog leg through eastern New

uinea and proceeding northwest along theWhile the Thirteenth (until almost the

of the war) and Fleet Air Wings 10 and 17in the Philippines, the Fifth and FleetWing 1 advanced to Okinawa and with thesaw action against the Jap homeland.

Australian and Royal New Zealand airunits operated with the Fifth and Thir-in the general southern area.

The Fifth and Thirteenth shared with theair wings, the Marines and the Allied units

the reduction of shipping in the Solomons andareas, attacking convoys and smalland pounding the isolated shipping

in New Britain and New Ireland. Bothoperated night low-altitude bombingfrom the Solomons and Bismarck

to the Philippines, both attacked the Jap

shipping and supply centers in the Carolinesand the Palau group, and both scourged thewaters of tiie eastern Netherlands Indies. Fromthe Philippines they operated against portsalong tiie China and Indo-China coast. The Fifthwent on to Okinawa and operated as the tacticalair force with the Seventh against the Japmainland and the waters adjacent.The fleet air wings operated night search andattack aircraft (Black Cats) along the whole

route from the Admiralties to the Philippinesas bases advanced west and north duringthe war, and conducted a great part of theever-extending daylight armed-reconnaissancesearches that finally left practically no part oftlie western Pacific seas and harbors uncovered.China-Burma.From China the Fourteenth

AF, when the locations of their bases permit-ted, bombed harbors along the Ciiina coast, andmined waters ne

USSBS Report 54, The War Against Japanese Transportation, 1941-45

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Transcript of USSBS Report 54, The War Against Japanese Transportation, 1941-45