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Given By t U. S. SUPT. OF DOCU^fENTS
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THE UNITED STATES STRATEGIC BOMBING SURVEY
Underground Production OF Japanese Aircraft
REPORT NO. XX
Aircraft Division March 1947
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THE UNITED STATES STRATEGIC BOMBING SURVEY
Underground Production OF Japanese Aircraft
REPORT NO. XX
Aircraft Division Dates of Survey:
2 3 October-25 November 1945 Date of Publication: March 1947 M(a3
A
0. S. SUHtKlWIENUtNf Of UUUUMtNCt
JUL 19 1947
This report was Avritteii priinavily for the use of the United States Strategic Bombing Survey in the prepaiation of further reports of a more comprehen- sive nature. Any conclusions or opinions expressed in this report must be considered as limited to the specific material covered and as subject to further interpretation in tlie light of furllier studies conducted by the Survey.
II FOREWORD
The United States Strategic Bombing Survey The Survey's complement provided for ;JOU
;as established by the Secretary of War ou 3 civilians, 350 officers, and 500 enlisted men. The lovember 1044, pursuant to a directive from the military segment of the organization was drawn ite President Koosevelt. Its mission was to con- from the Army to the extent of 00 percent, and uct an impartial and expert study of the effects from the Navy to the extent of 40 percent. Botli f our aerial attack on Germany, to be used in the Army and the Navy gave the Survey all possi- ounection with air attacks on Japan and to ble assistance in furnishing men, supplies, trans- stahlish a basis for evaluating the importance port, and information. The Survey operated nd potentialities of air power as an instrument from headquarters established in Tokyo early in f military strategy for planning the future de- September 1945, with subheadquarters in Nagoya, elopment of the United States armed forces and Osaka, Hiroshima, and Nagasaki, and with mobile or determining future economic policies with teams operating in other parts of Japan, the espect to the national defense. A summary re- islands of the I'acilic, and the Asiatic mainland. lovt and some 200 supporting reports containing It was possible to reconstruct much of wartime lie findings of the Survey in Germany have been Japanese military planning and execution, en- ublished. gagement by engagement, and campaign by cam- On 15 August 1945, President Truman requested paign, and to secure reasonably accurate statistics hat the Survey conduct a similar study of the on Japan's economy and war production, plant by ffects of all types of air attack in the war against plant, and industry by industry. In addition, 'apan, submitting reports in duplicate to the studies were conducted on Japan's over-all stra- Secretary of War and to the Secretary of the tegic plans and the background of her entry into Javy. The officers of the Survey during its the war, the internal discussions and negotiations apanese phase were: leading to her acceptance of unconditional sur- render, the course of healtli and morale among the Franklin D'Olier, Chairman. civilian jjopulatiou, the effectiveness of tiie Japa- Paul H. Nitze, Henry C. Alexander, Vice nese civilian defense organization, and the effects Chairmen. of the atomic bombs. Separate reports will be Harry L. Bowman, issued covering each phase of the study. J. Kenneth Galbraith, The Survey interrogated more than 700 Japa- Eensis Likert, nese military, government, and industrial officials. It also recovered and translated many documents Frank A. McNamee, Jr., Avhicli not only have been useful to the Survey, Fred Searls, Jr., but also will furnish data valuable for other Monroe E. Spaght, studies. Arrangements have been made to turn Dr. Lewis R. Thompson, over the Survey's files to the Central Intelligence Theodore P. Wright, Direrfom. Group, through which they will be available for Walter Wilds, Secretary. further examination and distribution.
Ill TABLE OF CONTENTS
Page
Inlroductioii 1
Paut I UndergioniKl Pl.iiils of Xak;ijim;i Aiicraft Company 2
Part 1 1 l^iulei-yidiiiid J'laiits of JMitsubislii Aiici-aft Company 33
Part 111 Minor Aiiciaft Companies 53
IV INTRODUCTION
Because the disspeisal ol' airi rail and engine manufactuiiiig' plants to uu-
(lei-gi'onnil locations proved to he fai- nioi-e extensive tlian had been suspected,
a special sttidy of undergiouml phints was undertaken by the Aircraft Divi-
sion. Lt. Col. J. W. Fredricks was assigned to the task. He made extensive
preliminary investigations of Munitions Jlinisfry, Army and Navy, and in-
dustrial records, followed up by tiehl in\estigations at many underground
sites throughout Japan. A summary of his findings ajiiiears in Section II of
the Aircraft Division's rejioit on "The .laijauese Aircraft Industry". The fol-
low pages comprise a series of "thumb nail" reports on several sites which he
visited.
714387—47—2 :
PART I UNDERGROUND PLANTS OF NAKAJIMA AIRCRAFT CO, OYA
AVlien Allied ;iir attacks toward the end of 1944 with stone quarries that provided large unde made it evident to the Nakajima Aircraft Co. ground areas already dug. The stone was rel that their plants were vulnerable, plans were tively soft and would therefore readily lend itse drawn to disperse them and, insofar as possible, to changes or expansion of the existing caves. place them underground. Oya and Shiroyama in Plans called for the utilization of two separa TawancliiGun, Tochigi prefecture, four miles underground areas and three surface areas f northwest of Utsunomiya were selected for the the manufacture of one engine type, the Japane dispersal of part of the airplane engine manufac Army designated Ha 45, Model 12 (1795 hp turing facilities of the Nusashi plant near Tokyo, This engine was the type used in the Prank Am and later for the dispersal of most of the air- fighter (Japanese Ki 84) which was being assa frame manufacturing and assembling facilities at bled at nearby rtsnnoiniya, and later was to Utsunomiya. This works, both engine and air- frame, was the best developed and most extensive assembled in other underground works in t of all the Japanese underground plants. Oya area. The following table gives details The area was selected largely because many of the engine works, and compares plan Avith acco: the surrounding hills were already honeycombed plishment
Location : wlch the photographs were taken are indicated
01 the drawing. he Benton ])lant was inlciidcd lo iJi'oducc ar iilating rods, master rods, gears, jigs, and mis-
: I neons small parts. Fignre 2 is the space and
liz^ition Inyont of the Itcnten jilitiit, Jilso show
II I lie number of machines planned and installed.
'iliigra])lis 7-10 on the following pages show or of the machinery. The photographer's po-
iii in each case is shown on the drawing.
lu' Knnnnia plant, above ground, was the site
I ill assembly, although it had originally been il lued that assembly would be done under- mid. The Yuba and Tage works were rela-
]-]y small and only a few pieces of equipment
1' installed. total of 1075 machine tools were acquired
1 the various works—76.5 from Musashi, 7G
I Omiya, 88 from Yokkaichi, and 146 from •iiibine known as Nippon Nainenki. Of these, jD, 604 were installed. ilans called for 14 test cells, but only 2 were coipleted. They were above ground, .so ventila- lai)n was not a problem. imployment reached a maximum early in iijust, 1945. The total for all the works was as fo iws
Direct E Regular Soldier Student >- oq: •-o < <
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3 i Photo No. 1. Crankcase shops, Tomiira plant at Oya Works.
Photo No. 2. Crankcase shop, Toniura plant at Oya Works.
6 Photo No. 3. Cylinder head shop, Tomiira plant at Oya Works.
Photo No. 4. Cylinder assembly shop, Tomura plant at Oya Works.
7 Photo No. 5. Cylinder barrel shop, Tomura plant at Oya Works.
Photo No. 6. Heat treatment shop, Tomura plant at Oya Works. Photo No. 7. Articulating rod shop, Benten plant at Oya Works.
Photo No. 8. Gear shop, Benten plant at Oya Works.
9 Photo No. 9. Entrance to Benten plant at Oya Works.
Photo No. 10. Jin and tool shop, Benten plant at Oya Works.
10 SHIROYAMA
graplis 1.") l(i show jigs and some of 3 troduction Ihe main air- frame parts. December 1044, tlie Nakajima Aiicraft Co. [u Tlie Kaneiriyama plant (86,000 square feet) dispei-se the airframe production fa- nted to contained machine tools and electric heat treat- ijities of its Utsunomiya plant, but the Munitions ment furnaces. Some space was used as a ware- [iiistry refused permission, saying it was not house. See photographs 17-20. it necessary. Finally, in March 1945, permis- The Tochigiyama unit, devoted to wing spar sn was granted and dispersal to underground manufacture, contained only 14,100 square feet, rerns at Sliiroyaimi bei;an. Tliis plant was op and all machinery had been removed at the time
ited in conjunction with the Oya plant, pre- the inspection was made.
iisly discussed. An ovei'-all layout of all parts of the Shiro- Planned production at Shiroyama was three yama installations is shown in Figure 3. The po- sition of the iij; assemblies and three fuselages per day but photographer in taking each of the the end of the war only four of each had been photographs on the preceding pages is indicated npleted. Manufacturing began late in April on the drawing l)y numbers t-orrcspondini; with numbers on the photographs. I."). The machine shop started first, then com- In July 1945, when dispersal lent manufacture, and in July, wing and fuse- was still going on from Utsunomiya to Shiroyama, the combined I e assembly began. number of employees was 21,117. This figure in- S'early all assembly facilities were to be dis- cludes both direct and indirect employees; no sed from Utsunomiya to Shiroyama, but some further break-down was available. re to be retained at Utsunomiya because the
I ice at Shiroyama was inadequate. Production
ganization The only airplane type intended for production at Shiroyama was the Army fighter Frank (Jap- )f a planned nineteen units in the works, with anese Ki-84). Nearly all sheet-metal parts and (total floor area of ()4!),7()0 square feet, only some machined parts were to be made here. Other ht units with 333,000 square feet of floor area machined parts came from the Tochig and Ot- me completed. Four of these (38,900 square awara plants of Xakajima but subcontractors t) were used as warehouses for tubing, ex- suj^plied 50 percent of all parts other than sheet- ded parts, duralumin bais, oil, and paints. metal pai'ts. fhe largest of the other four units that actually Actual airframe production amounted to only ^ into production was the Otomeyama plant four wing assemblies and four fuselages before (•4,500 square feet) where sheet metal parts the end of the war, but inasmuch as production •Me produced. Photographs 11-14 show the en- was just getting under way, those figures can nces and some of the presses. scarcely be used as any measure of capacity for jfhe next largest was the Watanabeyama plant the Oya plant. Three wing assemblies and three (v500 square feet) housing the wing and fuse- fuselages per day was the goal that had been ie assembly and jigs for tail parts. Photo- planned.
11 Photo No. 11. Tunnel entrances (Otomeyama plant), Shiroyama.
Photo No. 12. Tunnel entrances (Otomeyama plant), Shiroyama.
12 Photo No. 13. Sheet-metal press (Otomeyama plant), Shiroyama.
Photo No. 14. Part of 20-ton press (Otomeyama plant), Shiroyama.
13 Photo No. 1'?. Fuselage assembly shop (Watanabe plant), Shiroyama.
Photo No. 16. Horizontal stabilizer jigs (Watanabe plant), Shiroyama.
14 Photo No. 17. Machine tools awaiting installation underground, Kaiieiriyama Works at Shiroyac
Photo No. 18. Warehouse and stockroom, Kaneiriyama Works at Shiroyama.
15 Photo No. 19. Machine shops for airframe parts, Kaneiriyama plant in Shiroyama.
Photo No. 20. Electric heat treatment furnaces, Kaneiriyama plant at Shiroyama.
16 NO
OYA ENGINE WORKS
ASAKAWA
This plant was a dispersed location of the a third had a roller conveyoi- the length of the (isaslii Works of the Makajiina Aiiciaft ("o. and tunnel. Only h.ind methods were available in the
IS located in Die steep hills on the west edye of rest of the plant. akawa villafie which is two miles west of Most of tlie usual types of machine tools were ichioji in Tokyo prefecture. installed; engine latiies, turret lathes, drill It was jilanned that tiiis plant would liave presses, shajiers, phniers, giinders, etc. Eighty 3,000 square feet of floor space and l,l!0() nia percent of the 330 installed machine tools were ine tools for the production of 300 engines per American made, with such familiar company )ntli and tJiat it would be in production by July names as Brown and Shariie, (Mnciunati, Warner 15. However, at the end of the war in August, and Swazey, American Machine Tool, Bullard, ly G out of 31 tunnels were completed, with an and others in evidence.
?a of IT)", 000 square feet excavated. Thi-ee hun The six tunnels in o]ieration were used for ma- i(i tiiiity machine tools were in place and liad ciiining the following: m producing engine parts since July. Xinety- Xo. 1. e otiier machine tools had been delivered to tlie Cylinder heads.
e but not installed. No. 2. Cylinder barrels. The tunnels were laid out in tliree sections in a No. 3. Crankshafts. id network (Figure 4). No previous tunnels or nes had been in existence here so that the entire No. 4. Propeller shafts. eavation was new. External evidence of this No. 5. shafts. mt could be seen in the piles of spoil and in the Proi)eller w uncamouflaged surface buildings which were No. G. Engine accessories. ?d as offices and storehouses. The tunnels were approximately 15 feet wide The chief problems of operating this plant were d 12 feet high and varied in length from 100 caused by wet floors and moist atmosphere. The t to 1,200 feet. Because the rains caused tJie floors in all tunnels examined (Nos. 1 through 6) ifs of tlie tunnels to collapse in at least six were wet and in several places were under several ices, extensive timber shoring had l>een set. inches of water. This caused much illness among The Nakajima Co. expected to manufacture the workers and serious corrosion of tiie machines. ^ine parts in tlie underground woiks, with final At the time of inspection the machines weVe ienibly to be carried out in dispersed surface covered with a layer of grease and waxed paper in ildings farther up in the hills. By 1.1 August an effort to preserve them. Even so, many of them t5 about 10 engines liad been completed. In were seriously corroded. Photographs 21-25 show dition there were about 300 crankcase castings machine tools and parts in the plant.
)red in Tunnel 1, great stores of cylinder heads The manager of the jilant reported that a short- Tunnel 3, and many other stocks of engine parts age of new cylinders made it necessary to employ
^ machining. There were IS engines in process used cylinders in the manufacture of engines. This assembly in two dispersed small hangar-type was veritled in the assembly shop where the stock Hidings. of used cylinders slightly outnumbered the new For the conveyance of parts inside the tunnels, cylinders. 'o of the tunnels had narrow-gage tracks while Asakawa was inspected on 24 October 1945.
714387—47—3 17
GENERAL ARRANGEMENT OF ASAKAWA (UNDERGROUND) PLANT
Corrected to 13 JULY 645
JfflSHU HIGHWAY
AREA CHART
UNDERGROUND FACTORY
CONTOUR
SURFACE BUILONG
NOTE-.ShMt®of 2 RGURE 4
us. STRATEGIC BOWBWC SOHVFT UNDERGROUND PLANT ASAKAWA GEICRAL ARRANOEMENT
IltSIT O- 4t(rm«^ 1*>M
GOKAN
The (ioknii ])lant of the Nakajiiua Aircraft Co. awaiting the completion of new areas. In parts ;ir Nuuiata in (inimiia jjrefectiire was inspected of the plant, there were double rows of machine ('ai)tain Kicliarilson, the intelligeuce officer tools.
tlic oSTtli Infantry Regiment, 97th Division. The floors at Gokan, as at Asakawa, were gen-
II' lollowini; data were obtained from liim: erally wet and, while .some of the machinery was jSi.xteen tnnnels, each about 600 feet long, had protected with grease and tarpaulins, many other en excavated by 5G5 Cliinese prisonei's of war machines were severely rusted. 10 were housed nearby in a labor camp. Some A .semiunderground plant was l)eing built near- machine tools had been installed in the tun- liy to assemble the airframe parts which were to Is while many other tools were stored outside. be machined in the nndergi-ound section.
19 Photo No. 21. Asakawa underground plant.
20 Photo No. 22. Asakawa plant cylinder heads awaiting machining. Note roller conveyor.
Photo No. 23. Asakawa plant. Cross-tunnel used for storage of engine parts.
21 nil *=;=* 1^
^. -\ -C^V* pa
1 ''-r-r YOSHIMATSU
One III' Ilic iiKisI ;iii\ Mined |il;ni1s seen in Japan tunnel areas were comiileled, maciiine tools were ivas till' Voshinialsn ent;iii(' (ilant of Nakajima installed and the machining of aircraft engine ociitcd iH'ar .Malsiiyaiiia, ''<- miles noitlnvest of parts was begun. The first actual work was done Tliis jilant. wliicii was (lis]KMsc(l fi-om Tokyo. the on 1.") June and continued nnfil the end of the Omija Works, ^vas SO peicent coniplele and -was war. ])rodii((ioii from lo .huie until of in the end the Tlie total planned area of this plant was 353,000 Altlionj^li it was planned to make eomplete win. square feet, to be spread over six areas (Figure iigines a1 this plant, only the nnicliininy of parts 5 1 . The first five areas were completely excavated actnally earried ont. ivas and tliree tunnels of the sixth area were com- The Japanese aircraft indnstry was not tlie first pleted, making a total excavated area of about irganization to i^o nndeij^ronnd at ^Matsnyama. 320,000 square feet. The total length of tunnel riiat distinction jioes to a jironp of cave dwellers amounted 1o approximately 33,000 feet. )f abont 1, .")()() years ajio. More than 100 caves Each tunnel was 13 feet wide and varied in pockmark tlie face of the cliff in which the air- height from 11 feet to 13 feet to accommodate the raft tnunels aie located. Each of these caves has use to which the tunnel was put. (Photographs in entrance aliont 4 to 5 feet square which opens 28-36). into a heniisjdierical room abont 8 to 10 feet in The tunnels were fairly dry due to the peculiar iiameter ( l'lioto};iaphs 20 and 27). These caves desiccating quality of the volcanic-type rock ivere the dwellintis of some ancient tribe. through which they- were carved. The tempera- Farther alony tlie clitT is anotlier cnriosity—the ture remained fairly constant underground Madman's Hotel, which is an underground house throughout tlie year. No. 5 tarted by Ninekichi Takaliashi in Nishi-Yoshimi- Area was shored up by timbers but most of the inura. Tlie house was begun in the thirty-seventli remainder needed no rear of the reign of Meiji (1904) as a financial siqiport. In many places concrete floors had been reuture. He expected that it would take three laid.
enerations to complete but by that time it would Four hundred fifty machine tools had been
36 such a curiosity that visitors would pay to see brought to the site but only 300 had been installed 'ventnally become financially independent. ill single rows. He worked for I'O years on the project and had Corrosion of equijunent became a problem 2 large rooms, 1 small room, numerous corridors, almost at once. To combat this condition it was ind the staircase to the second floor already made the responsibility of each workman to keep ai'ved. The entrance was flanked by 2 Grecian his machine from rusting. To prevent corrosion, olnmiis carved into the cliff si i by 12 feet had stone tables, chairs, and fixtures. per month in the underground plant, with final The dreams of Takahashi were not realized as his assembly in dispersed buildings in and near 5on abandoned what he considered to lie a mad- Matsuyania. Actual production, however, con- man's project when the father died. sisted only of master rods, cylinder heads, cylinder Both of these projects served a useful purpose barrels, and crankshaft counteilialances. Between for the Japanese in 104."). as they inspired the 200 and 300 of each of the above parts were com- onstruction of an underground aircraft plant in pleted by 15 August. this hill of sedimentary volcanic ash. Evidence of this work was seen in the piles of On 15 January ]()4.">, this factory received master rods, counterbalances, and cylinders that orders to go underground and excavation was were stacked lieside the machine tools and in stor- started shortlv thereafter. As sections of the age tunnels. 23 : Eventnjtl employnieiil lieie would have been chines seen anywhere underground were i J;,000. Uowever. ouly -"iOd weie iKtiially at work place here. undei-ground in Aiijiiist. K. Hiruta was plant .">. A power substation of three 2o0-kv.= i. manager. transformers was built for each of the e Transportation of parts to and from the plant completed areas. was by truck. 4. Tunnel cross sections varied to suit the m\ Several tnnisiial featines were noted in this plant The entrances to Sections 1 and 6 were iu sh i cliffs at least 75 feet high. The whole establ 1. In area No. i. nine heat treatment pits were ment was well concealed except for a built being dug in the tunnel floor. Each pit area of 5 surface buildings (warehouses, offn measured S feet wide, t! feet deep, and lo feet long. etc.) near the entrances to Number 4 area. 2. Tall machines Avere coiiiUersunk into the Yoshiinntsu was inspected on 13 and 15 Novi floor of the tunnel so tliat the largest ma- ber 1!)45. I 24 I ^- ^K^^'^-.Ji-^ti. m^ ^5^-^ Photo No. 26. Ancient caves at Yoshimatsu. Photo No. 27- Close-up of ancient caves at Yoshimatsu. 25 Photo No. 28. Entrance to Nakajinia tunnels at base of cliff, Yoshimatsu. I'hoto No. 29. Entrances to tunnels, Yoshimatsu. 26 Photo No. iO. Machine tool in process of installation, Yoshimatsu. Photo No. 31. Tunnels at Yoshimatsu. 27 Photo No. 32. Machine tool in process of installation, Yoshitnatsu. Photo No. 33. Machine tools in position, Yoshitnatsu. 28 w^ Photo No. 36. Heat treatment pits under construction, Yoshimatsu. 30 YABUTSUKA The Yabiilsuka aiifiiuue plant, located 6 miles Thirty tunnels, each 13 feet wide and 11 feet (ulliwest of Ota, Gumma prefecture, was a ilis- hifih, were completely excavated and shored up ersed location of the Ota "Works of the Nakajima with timbers. This represented one-half of the ircraft Co. |)rojected ai'ea. Tt was not possible to inspect the tunnels of Excavation was started in January 1945 by lis ]ilant on the date of visit, 13 November 1945, 1,500 men working on a 10-hour shift. Planned pcause all entrances had caved in. The local lay-out is shown in Figure 6. 'i|ianese attributed the collapse to the torrential No machine tools were installed or even brought ( lober lains and denied that any explosion had to the site. ;ilcd them. At several entrances it was possible liiok over the landslide into the tunnels where This plant was almost inaccessible. Only one rcmld be seen that water was standinj; from 1 very narrow road which would barely permit pas- feet deep. sage of a jeep led to the site of the plant. YUSENJI \ usenji, 1 miles west of Komatsu in Ishikewa An extensive network of tunnels and quarries is efecture on the northwest coast of Japan, was hidden under the hills witii only a few entrances dispersed airframe plant of the Handa Works and some new spoil to reveal their existence to the the Nakajima Aircraft Co. photo interpreter. Small entrance tunnels about The underground areas of tliis plant were the 9 feet wide and 6 feet high with extensive and riad and irregular caverns of ancient firebrick heavy shoring led into the main galleries which id modern stone quarries. In prewar years many were of irregular shape (Fig. 7). the modern buildings of Tokyo and Osaka had Concrete bases had been laid on which to mount in constructed fi'om building stone dug out of site. the machine tools and the cavern floors were dry. >f a planned area of 211,000 square feet, about Yusenji was easily accessible by highway and "000 scjuare feet were ready for use, while 100 electric raili'oad from Komatsu. The actual tun- 400 machine tools planned were in operation. nel level is only a few feet above sea level. . The jilant was designed to produce small air- Of all the underground factories seen, this one Ibme parts, metal fittings, and similar items for seemed among the best from the standpoint of e C-6 scouting plane. Production on a small transportation, concealment, and working condi- ale began late in June 1945 but only a few parts tions. ?re completed by the end of hostilities. The con- One half mile north of the Nakajima site was rsion of the caverns for aircraft production be- another hill with a similar network of caverns, iin in February 1945 under Navy supervision and jnipletion was set for the end of September, but which housed great stores of munitions that were ily 30 percent progress had been made by 15 being removed by United States troops on 20 iigust. November 1945, the date of inspection. 31 LAYOUT OF YABUTSUKA PLANT U.S. STRATEGIC BOMBING SURVEY UNDERGROUND PLANT YABUTSUKA FlCjUfiE 6 THin O - 41 IFiCB (I IJI ^ .^.U o 5 ENTRANCE YUSENJI UNDERGROUND PLANT HEIGHT VARIES FROM 5i FT TO 16 FT OF [ SLANTED LI^CSAfiE•4 TUNNEL GROUP MACMNE TOOLS KSTALLEDJ NAKAJIMA CO. i^*3 ENTRANCE USSTRATEGC BOMBING SURVEY YUSENJ UNDETfGROU\D PLANT (OSPEHSED FROM HANQA VKJfilS OF NAKAJIMA-) F)&-r T10*T O - «T iru> K HI Ho. 1 PART II UNDERGROUND PLANTS OF MITSUBISHI AIRCRAFT CO. KATSURA The Katsuia plant of Mitsubishi No. 8 Engine Seventy two machine tools had been installed Woiks was located at Mameda, one-quarter mile and were in operation from June 194.1. The entire north of Katsuia station, southwest of the plant was used for city of the machining of all master Kyoto. Not strictly rods for Kasei an underground plant, it was 25 engines. au interesting It was evident that the use of a lailroad viaduct lo con- plant had been an effi- cient one. It ceal and protect a shop. was clean, well-lighted, and dry, with an orderly The arrangement of machine tools.' space under the viaduct where it crossed a In external appearance there was no liighway was enclosed by the erection evidence of mud walls to reveal the location of this plant to the photo along the steel and concrete trestles. The area interpreter. thus enclosed amounted to 25,000 square feet. The jilant was inspected on :'.() October 194.1. OTANI The Otani plant was a dispersal location of the plant. Many of the employees were girl students Mitsubishi No. S and No. 14 Engine Works and who "worked very hard but not too well.". More wa.s situated at Otani, 1 mile southwest of Otsu, than half of the machine shop employees were a city 6 miles east of Kyoto. students. Two abandoned railroad tunnels, 2,1(50 and The tunnels were reasonably dry but the man- 2,1'OU feet long respectively, were used as gear- :iger leported that there was always trouble with tutting and grinding shops for the aforementioned moisture, which caused worker illness and cor- Iilants. Thirty-six different kinds of gears were rosion of machines and tools. machined here on 2S6 machine tools belonging to Six wooden buildings were erected in the valley ^'o. 8 Works and 2.5 tools belonging to No 14 at the southwest end of the tunnels. The.se build- Works. ings were to be used for heat treatment, carboni- Installation of machine tools began 16 JIarch zation, and copper plating but were not completed 1945 and was completed in April. Full produc by the war's end. They were not camouflaged nor tion was carried out for 2i/o about months. was it intended to do so. A total of 700 persons was employed in the The plant was inspected on 31 October 1945. KIYOTAKI Kiyotaki was a dispersal of Mitsubi-shi No. 14 Otani. The tunnels were 1,970 feet long and lMij,'ine \'\'(irks and was located in two abandoned housed 120 machine tools. **'ieetcar tunnels 5 miles west of Kyoto. Machining of exhaust valves was the only opera- The plant was very similar to Otani and came tion to take place here. into production in May 1945, just ten days after 714387—47—4 33 KUKURI conceal the entrances to all but three tunnels The Kukuri plant of the Mitsubishi No. 4 and become the only entrances. Engine Works was located in the hills three miles wliich would then sixty-four of a planned 800 ma southeast of lliromi, about 20 miles northeast of One hundred underground. Thesi Nagoya (Fig. 8). chine tools were installed An elaborate netwoi-k of 38 tunnels totaling machines were lined along both sides of the tun of 23.000 feet in length was excavated in a ridge nels, leaving an aisle about four feet wide in th' planned area sedimentary-type rock. The total center. which 270.000 square was 360,000 square feet, of This plant was supposed to manufacture engine feet were completed. In cross section the tunnels liut no actual production was achieved. 16 feet wide and 11.5 feet high (Figs. measured These tunnels were among the better ones see 9 and 10). in Japan. They were very dry, well laid ou' During construction the tunnels were cut en- had smooth floors, and seemed roomier than mam tirely through the hill so that the machine tools others (Photographs 37-40). could be handled directly into each tunnel. After Kukuri was inspected on 3 November 1945. the machines were in place it was intended to close I 34 > UNDERGROUND PLAI li...«| PILOT TUNNELS ^^ ENLARGING UNDER CONSTRUCTION' ^^ ENLARGING FINISHED IQO 200 MO U.S. STRATEGIC BOMBlNG SURVEY KUKURI UNDERGROUND WORKS AUG. IS, IMS Turn 0- «T(rK»p. Ml* TltSRT O - 41 (Pi» p. SB) No. 1 \ 3 3 JS 01 u a X 6 Z o o j3 37 "fli Photo No. 39. Kukuri plant. Two long rows of machine tools Photo No. 40. Kukuri plant. Machine tools being installed. 39 : NIKODA The Xikoda undergroimd plant of the Mitsubishi was realized and no machine tools were install No. ") Airframe Works was situated in the hills 6 At the war's end the underground plant wa.s miles west of the city of Ueda in Nagano prefec- per cent complete, the power installations were ture. per cent complete, and the semiunderground pli Orders for dispersal into the Ueda area were was 45 per cent complete, with 33 buildii received by Mitsubishi from the Army in April erected. 1945. The actual excavation of the underground The schedule called for total completion of plant was supervised by the Army. The techni- underground plant in September 1945. cians in charge came to Nikoda after completion At the time of inspection the tunnels were > of the Central Army Underground Headquarters and damp. When asked what precautions agai at Matsushiro. between Nagano and Ueda. Three worker illness and machine corrosion had b areas were planned with 17, 6, and 15 tunnels, taken, the plant manager replied that there \ )-espectively. Each tunnel was to be 13 feet wide no time to study any problem other than that and 10 feet high and shored witli timber to prevent getting the machines underground. roof collapse. Transportation of material to and from Tlie production goal was an output of 50 Ki-83 plant was expected to be by truck only. aircraft per month in conjunction with a nearby Tlie inteiviews and inspection were conduc semiunderground plant. However, no production on IL' November 1945. MATSUMOTO The -Mitsubishi No. 1 Airframe Works had a Nagoya to Matsumoto and later, to transport combined underground and semiunderground terials to the underground site. Transport to I)lant under construction several miles southeast underground plant from Matsumoto was by tri of Matsumoto in Nagano prefecture. over narrow and poorly maintained roads. This plant was designed to produce 20 experi- The schedule called for 50 percent complet mental aircraft per month. The planned area was and the beginning of production in June 1945 i 25:i,000 square feet, all of which was excavated, for total completion in August. Due to the d but only 40 percent of it was ready to receive ma- culties already enumerated, only 40 percent o chine tools. No machine tools had been installed, pletion was reached in August. however, and there was no production. The familiar comment was again stated he Plans were made in February 1945 to go under- the great haste of dispersal left only time to c ground at this location and work liegan on the sider tlie basic problem of getting the mach tunnels in April under the supervision of the tools underground and out of reach of the An Army. Although the original survey conducted ican bombers. Such serious considerations by the Army concluded that no shoring would be protection of machinery against corrosion, vei needed, the rock proved unsafe and extensive shor- lation, and worker health were postponed. Even ing with timber became necessary. It was planned IfD ally, Mitsubishi hoped to solve these problems to use concrete to support the weak spots in the lieat and ventilation. tunnels but a shortage of cement prevented this. I'arts fabrication for Ki-83, Ki-67, Keppn, a In fact, timber also became scarce very soon, when underground. Fii three times as much timber as calculated was Taiyo was to take place needed. assembly was to be accomplished in the 150 sei An insufficient number of underground buildings in the surrounding hi mining engineers 11( added to construction problems. Testing was to be done in semiunderground bui Transportation, however, proved to be the chief ings at nearby Murai airfield. problem in going underground, first, in the move- The date of inspection of Matsumoto was ment of machine tools and equipment from November 1945. 40 OGAMI Jhe Ogami imdergiound plaut of Mitsubishi No. plete Init progress toward actual production was Airframe Works was located 10 miles south of only 10 percent advanced. ibka in Toyama prefecture. A semiunder- Tunnel cross sections measured 13 feet by 10 luud plant at Haiinyamura was operated in feet after shoring had been erected. The maxi- se conjunction with Ogami. mum tunnel length was 1,150 feet. No machine I'his plant was still under construction by the tools liad been installed. ernment and had not yet been taken over by Ogami was inspected on 18 November 1945. subishi. The excavation was 30 percent com- NUKATANI 'lie Nukatani underground plant of Mitsubishi Furtheimore, the problem of transportation of 12 Engine Works, four miles south of Kana- both workmen and products presented even more •a, was one of the most unusual plants to be serious problems than those which already had ted. caused great difficulty in other more desirable "he necessity for performing a certain amount locations. mountain climbing to an altitude of 750 feet Despite these considerations, the plant was con- t strange a air to the Nukatani underground structed to house one of their more important ut. The plant was accessible only on foot up works to produce exhaust turbines and fuel injec- larrow, recently constructed road which was tion pumps. Beginning 10 July 1945, machine ihed out in many places by the heavy October tools were laboriously pulled up the mountain IS. road by hand and roller means and by the end of Lucient caverns, from which the people of a the war 146 machine tools were in place. In t age extracted tire brick, were at first intended addition, 253 tools were stored at the base of the the Japanese Navy to be used as a Naval hill in shrines and schoolyards. Almost all of the anal. Early in April 1945, the Navy started machine tools were of American make, because k on making the tunnels and caverns usable of the high degree of accuracy required in making late in the same mouth abandoned the project these parts. turned it over to Mitsubishi for aircraft- Actual production had not yet begun but ine production. was anticipated within a short time. litsubishi subcontracted the construction of The caverns and tunnels were very dry and in plant and the company was to be reimbursed many places concrete floors laid. It r by the government. Because of the inacces- were was not necessary to the pil- lity of the site, it became necessary to initiate shore up caverns as natural rge civil road building project to the plant, a lars and the strength of the rock itself were dential building program, and a bridge con- sufficient support. ctiou program to span the steep chasms to the Located on many levels throughout the moiin- t. tain, the tunnels ranged in elevation from 650 to itsubishi did not approve of Nukatani but was 800 feet above sea level. The average cavern was er constant pressure from the government to 20 feet wide while the height varied from 12 to 20 d a plant at this location. The company's feet (Fig. 11). obction was based ou the knowledge that, in During the early summer of 1945 the Japanese K itioii to being inaccessible, the plant also Navy made aerial reconnaissance of the area and *''ild probably be out of production for four reported that the new road revealed the location Ti'itlis each year because of the heavy snows in of the jjlant. liwest Honshu duiing the winter months. Nukatani was visited on 19 November 1945. 41 SHAKUTANI Shakiitiiiii, located one mile west of Fukui city This plant was well advanced (considered ill Fnkiii prefecture, was an underground disper- percent complete by the Mitsubishi Co.) by t sal of Mitsubishi No. IS Engine Works. average standard of underground plants. In adi This plant was an elaborate arrangement of tion, it was near the local ground level and w caverns and tunnels consisting of four completed easily accessible by highway. underground areas as well as a semiundergrouud The caverns and tunnels were very dry, nev; plant (Fig. 12). So skillfully were the semiunder- theless, most of the machine tools were corrodt grouud plants built into the hillside that one The caverns followed the seam of building sto building was almost passed during an inspection and were therefore of varied size, on many diff( trip before it was noticed. ent levels, and of generally high ceilings (12 to Caverns from which Shakutani stone—a famous feet). Only one landslide occurred during t Japanese building stone—had been removed, fur- October rains. nished the s])acc for this plant. Work was started The machine tools for one area were lower in February Iflio to ready the caverns for use by into the tunnels through a vertical shaft 60 fi the Mitsubishi Co. and the movement of machinery long. into the plant began in April. This jjlant was to produce gears and light mei The machine tools, of which !'!)(! had been in- parts for engines. stalled, were only in the process of alignment and The date of inspection was 21 November 19 testing, and it was claimed liy the company that no production was achieved. SABAE Stone ((uariies :?()() feet above ground level pro- cials that no productive work had emanated frc vided the setting for the Shinyokoe plant of the this plant by 15 August 1945. .Mitsubishi No. 18 Engine Works at Sabae in The newly excavated tunnels near the base Fukui iirefeclure. the hill were among the best of this type that we This plant consisted of two sections, the first seen (Fig. 14). The rock was dry and solid ai being in the stone (juarries well up into the hill, no supporting timbers were needed to reinfoi ((insisting grid of excavated the roof. Some extremely tunnels the second of a newly roomy ( tunnels at ground level at the base of the hill. undergiound standards) were inspected. Sever The (piarry section was a series of caverns with tunnels were 20 feet by 10 feet in cross sectic large rooms and lofty ceilings. One room was dimensions. A total of 13 tunnels, each about 3 fully 7."> feet long. 2.") feet wide, and IS feet high. feet long, had been completed but no machine too Concrete floors had been laid in many places and were installed. throughout the tunnels it was exceptionally dry. The entire lay-out of this plant was excellent As may be seen from the attached drawings, concealed from the standpoint of aerial reconnai (Figs. 13A and 13Bj the caverns are not syste- sauce. Only a very small amount of spoil wi matic but wind about in eccentric patterns and visible and the roads were almost completely coi are on many levels. At one place a broad flight of cealed by trees. The plant was accessible t stone stairs elicited the comment "It's just like a Sal)ae by an existing road. cathedi'al underground." The impression gained was that this plai This upjier section of tlie jjlant had been wired would have become a good ]iroducer of engin for electric jiower. Two 200-kv=a. transformers parts within two months and that it would hav and a switchboard had been installed. been comparatively safe from direct bombin Twenty six machine tools were in position in attack. lireparation for the jiroduction of cylinder heads. The Sabae area was inspected on 21 Novembe A large stock of iiimiachined cylinder heads was 1945. on hand Imi it was maintained liy company offi- 42 UNDERGROUND FACTORY MITSUBISHI CO. [:;:|:;:j COMPLETED iN I j pfiocess PLANNED NOTE 9 HOLES- TOTAL FLOOR AREA" IC^eOOSO.FT (NO 20 TO 29 HOLES- 146 MACHINE TOOLS) TOTAL AREA - 395^00 SO. FT ELEVATION IN FEET US. STRATEGIC BOMB SURVEY UNDERGROUND PLANTS NUKATANI LAYOUT OF SHAKUTANI PLANT UNDERGROUND NO Of HOLE LEGEND r ELEVATION ABOVE SEA LEVEL ROOF HEIGHT USHIGAYA STONE QUARRY Ua STRATEGIC BOMBINo SURVEY UPPER LEVELS OF PLANT AT SAKAE Fie. 13 43 44 il 45 UNDERGROUND FACTORY LAYOUT •OALi m ntr (machine shop) .o. :o!r<^ MACHWE TOOL (oM pits of clMning sond uMd I 1 in plodng of nMcMn* tool) ^^g POWER HOUSE EQUIPMENT («wfteti bott ttc.) PASSAGE us inMt&it Muem ajBVEV HIGHER FLOOR {viry dongtrout in this or«o N(SAI UNOERGROUNO WORKS a bilow bocous* of lonMidM) OF MITSUBISHI 1l»t^ O . 4T (PI» t Ml HISAl The Hisai plant (Fig. 15) was< ouly one of a Concrete had been laid as machine beds but series of iin(lei Co., in addition to Jritsnbishi, had nn The Hisai underground plant, located in the The estimated capacity of the plant when tin- low hills southwest of Nagoya, was a part of the islied was 1,.")()0 workers and .540 machine tools, .Mitsubishi No. 3 Airframes Works. actually, 300 tools were installed, beginning in At Hisai, entrances led down to a working level lune 194.5. some 40 feet deep. The tunnels had been hol- This plant was dangerous in several areas be- lowed out of the sandy rock and very little shor- cause the tunnels were on two levels and the ing was necessary (Photographs 41-47). collapse of sections was imminent. 47 Photo No. 41. Machine tools en route to Hisai. Photo No. 42. Entrance at Hisai. 48 it G a o o til o z o Xo 49 "3 O _2 -f 6 Z 50 Photo No. 45. Interior at Hisai. Photo No. 46. Interior at Hisai. 51 52 PART III MINOR AIRCRAFT COMPANIES SOGO DEPARTMENT STORE PLANT OF THE SUMITOMO COMPANY 111 Osaka, tlie si'cond and lliird haseiiieiits of sidew;ilk adjoining the building. This work had lie Sojjo Co. l>ei(artnu'iit Ston- were used by the been carried out at night so as to conceal tlie uinitomo Co. for the maeliiiiing of propeller whole operation. The heavier machines were in iirts. the third basement and the lighter ones in the Xot strictly an iiiidergroniid jilaiit, the.se base- second basement. iciit.s were inspeeted to complete the picture of In great contrast to the tunnel plants, these ic various types of underground installations. basements offered no unusual ojienitional .V total of 167 machine tools operated here for prob- lems, clean, period of 3 months in wliat appeared to be an were light, dry, and efficient. Further- ii-derly and well-managed production line. more no external evidence was visible to (he photo The machine tools had been lowered into tlie interpreter of the actual work taking place here. isements througji holes that had been cut in the This plant was visited on 30 October 194;). HANDA The Handa underground plant of the Sumitomo on occasion to lemove tlie water. (Photographs II. was a part of the network of underground 48-51.) ants southwest of Tsu (40 miles" southwest of There were no rail communication tunnels as agoya) to serve the Tsu Naval Arsenal (Fig. 16). at Hisai and the machines were moved in by This plant was similar, but superior to, the hand. isai plant of Mitsul>ishi whicli adjoined it. The Enlarging of tunnels Iiegan in March 194") and iiinels were enlarged out of tunnels which had completion was planned for Septemhei-. Of a en dug previously to furnish sand for abrasives. jilanned 4,500 employees and 640 machine tools, Frequent shoring, cement spray on the walls, 725 employees and 271 machines were at work. ip guards over the maciiines. concrete floors, Handa was to produce ]iropeller parts. The joping levels, and drainage gutters were char- plant was in operation but only a few parts had 'teristics of this plant. Pumping was necessary been finished. 53 UNDERGROUND PLANT LAYOL n r # 1^t> D' y^- S3: 'O Q (o. o D SCALE IN FE£T US STRATEGIC BOMBING SURVEY suMrroMO underground plant AT HANDA.TSU CITY FIGURE 16 Photo No. 48. Interior at Handa. Photo No. 49. Entrance at Handa. 55 Photo No. 50. Handa plant. Tunnels in sand mines near Tsu City. Photo No. 51. Handa plant. (Note production tunnels opening into communications tunnel.) 56 TAKATSUKI The Takatsiiki nii(l('ij>i-oiiiHl plant of the Kawa- were near production. Forty machine tools and saki Aii-cralt ("o. was located near Nai'iai village electric power had been installed and production (III the outskirts of Takatsuki, which is midway was to get under way on or about UO August 1945. between Osaka and Kyoto. Mute evidence of the cessation of the war could t)riginally intended for use as a central Army be seen in the abandonment of machine tools warehouse, these tunnels were begun in November poised over the edge of a cliff, preparatory to be- IWi by the government. Their use by Kawasaki ing hauled into the tunnels. Steel plates were was not ordered until February 1945. A force of used as a base for sliding the tools into place in 3,500 Koreans living in the valley was engaged the tunnels. in the construction of this plant. At the time of inspection, 30 October 1945, the The tunnels, totaling a planned 300,000 square tunnels were fairly wet despite the fact that sev- feet of floor area, were laid out in tw^o adjoining eral of them were faced with concrete. Timber, iiills, but only one area had reached any appre- expected to last for year and a half, was used in ciable stage of completion (Fig. 17). many places as shoring. Tlie completed tunnel system was halfway up At a later date the company expected to install a roughly circular hill, 1,680 feet in height. Laid electric heating and ventilating. out in a grid network were 16 tunnels with 100,000 This plant was constructed for the purpose of square feet of floor area and a planned machine making parts for the Ha-140 inline engine for tool capacity of 550. However, only six tunnels Tony II. SETO The Aiclii Aircraft Co. dispersed a part of its damp. Shoring was necessary throughout. (Photo- works to tlie hills north of Seto, a town about ten graphs 52-61.) miles east of Nagoya. This plant was to make wings for Judy at first, A planned and completed floor area of 110,000 and later, to make the entire airframe except for s(|uare feet was excavated in Ave areas, under five linal assembly. adjoining hills. However, only 45,000 square feet It was planned to install 800 machine tools, of were in use. which about half were ready for use. Production The tunnels formed an irregular pattern (Fig. was under way by 15 August 1945 but only a few IS). They were fairly spacious but, in the usual wing spars were made. fashion of underground plants were wet and 57 58 I Photo No. 52. Cave-in of machine shop at Seto. Plioto No. 54. Camouflaged entrance at Seto. Photo No. 55. Entrance at Seto. 60 "i/v '^^ •-,. S'.tN- Photo No. 56. Entrance at Seto. Photo No. 57. Surface building at Seto. 61 Photo No. 58. Seto plant. (Note extensive shoring.) quarters shown here were not uncommon.) Photo No. 59. Seto plant. (The tight working 62 Photo No. 60. Interior at Seto. Photo No. 61. Interior at Seto. 63 HIRO PLANT OF llTH NAVAL AIR DEPOT Plans for underground production were made moved to Takihara. This movement was to in April 1944. Construction and conversion of completed by June 1946. At the time of the ; the tunnels were begun in November 1944. The raid on Hiro on 5 May 1945, over 90 percent first movement of equipment to the underground the small and medium sized machines had alrea tunnel was in January 1945. The principal under- been moved underground. At the end of the v ground facilities were converted from a large about 99 percent of the machines had been undei'ground hangar which had been built in 1940, stalled in the underground plants. and an adjoining road tunnel. Actual production In June 1945, the Hiro Navy Yard converted was begun in these tunnels at the end of January facilities for making marine engines to the maj 1945. It was planned to move all the smaller ma- facture of aircraft parts. Its machines were chines to these tunnels. One-half of the remaining eluded in the underground dispersal. Plans large machines were to stay in the surface build- these underground plants called for product: ings at Hire, while the other half were to be of 400 engines a month by April 1945. late UNDERGROUND PLANTS irtl inal Intelligence Check underground tunnels through air photo inter| tation. Postwar photography and interpretati Wiutime knowledge of Japanese underground even when based on information supplied installations extremely meager. Allies was The USSBS, was unable to find most of the entran knew the locations of only three installations and at the locations that had been studied by USS nothing more. This was probably due to the fact And it was impossible to state how extensive- that the underground not really program was underground plant might be or what activity i begun until the last year of the war and there was being conducted in it. not enough time for the information to seep out The principal way of learning about un( into Allied hands. grounds would seem to be by POW interrogati Anotlier cause was the difficulty of finding augmented by air photographs. 64 CONCLUSIONS "lie .Tiijianese underground installatious wei-e Interdiction of highways and raili-oads leading nil too late for them to be able to save the pro- to an underground retarded production by ob- liiiii of aircraft. In any event, their existence structing the receipt of materials and tiie delivery 111 not other problems such as have overcome of finished goods. Destruction of electiic power I la.ues of vital raw materials and fuel. sources might have had the same effect. I instruction methods do not reveal anything The principal advantages of an underground t is new or that is not already known to the in.stallation are that it is hard to find, makes a 1 engineering profession. Only the profusion very poor target and would probably l)e safe from iiiinels, caves, and mines is impressive. any weapon used in the second World War. Heavy iiherent dampness wreaked havoc with preci- gases would make an underground untenable but luachinery and with the health, morale and could be countered by air purification devices. iiy of workers. Air-conditioning and water Bacteria would be effective against workers whose iuage were necessai-y for any long period of vitality and resistance had been lowered by work- .It ion, if machinery was to be protected ing underground. I list rust and corrosion and still be in use. iildition, workers need to be fortified with an However, in spite of the disadvantages, it would mate diet. Workers also need plenty of light seem advantageous for any nation to ]int some of luk by. Sun lamps would probably have been its more vital production facilities into adequately licial to the workers. prepared underground locations. If the Japanese nderground production probably suffered from had made an earlier start on their underground lack of free and simple transport such as is program their underground and dispersal plants i liable in a compact, well-planned surface fac- might have constituted a more serious problem for the Allies. 65 ) : UNITED STATES STRATEGIC BOMBING SURVEY LIST OF REPORTS The following is a bibliography of reports i-esulting Light Metal Branch from the Survey's studies of the European and Pacific 20 Light Metals Industry (Part I, Ahnninnm wars. Those reports marked with an asterisk (*) may of Germany )Part II, Magnesium be purchased from the Superintendent of Documents at 21 Vereinigte Deutsche Metallwerke, Hildesheim, Gi the Government Printing Office, Washington, D. C. many 22 Metallgussgesellschaft G m b H, Leipzig, Genua European War 23 Aluminiumwerk G m b H, Plant No. 2. Bitterfe Germany OFFICE OF THE CHAIRMAN 24 Gebrueilcr (Jinlini G m b H, Ludwigshafen, 6' many •1 The United States Strategic Bombing Survey : Sum- mary Report (European War) 25 Lnftschitfbau. Zeppelin G m b H, Friedrichshaf *2 The United States Strategic Bombing Survey on Bodeusee, Germany Over-all Report (European War) 26 Wieland Werke A G, Ulm, Germany 27 Rudolph *3 The Effects of Strategic Bombing on the German Rautenbach Leichmetallgiessereien, Sol War Economy gen, Gei-inany 28 Lippewerke Vereinigte Aluminiumwerke A Lnnen. Germany AIRCRAFT DIVISION 29 Vereinigte Deutsche Metallwerke, Heddernhei (By Division and Branch) Germany 30 Duerener Metallwerke A G, Duren Wittenau-Be^ *4 Aircraft Division Industry Report & Waren. Germany 5 Inspection Visits to Various Targets (Siiecial Report AREA STUDIES DIVISION Airframes Branch *31 Area Studies Division Report 6 Junkers Aircraft and Aero Engine Works, Dessau, 32 A Detailed Study of the Effects of Area Bomb> Germany on Hamburg 7 Erla Maschinenwerke GmbH, Heiterblick, Ger- 33 A Detailed Study of the Effects of Area Bombi many on Wuppertal S A T G Maschinenbau, G ni b H, Leipzig (Mockau), 34 A Detailed Study of the Effects of Area Bomb Germany on Dusseldorf 9 Gothaer Waggonfabrik. A G, Gotha, Germany 35 A Detailed Study of the Effects of Area Bomb: 10 Focke Wulf Aircraft Plant, Bremen, Germany on Solingen Over-all Roiwrt 36 A Detailed Study of the Effects of Area Bomb) 11 Messerschmitt A G, Part A on Remscheid Augsburg, Germany Part B 37 A Detailed Study of the Effects of Area Bombi ApiK-ndices I, II, III on Darmstadt 12 Dornier Works, Friedrichshafen & Munich, Ger- 38 A Detailed Study of the Effects of Area Bombi many on Lulieck 13 Gerhard Fieseler Werke G m b H, Kassel, Germany 39 A Brief Study of the Effects of Area Bombing 14 Wiener Xeustaedter Flugzeugwerke, Wiener Neu- Berlin, Augsburg, Bochum, Leipzig, Hagen, Do stadt, Austria mund, Oberhausen, Schweinfurt, and Bremen i Aero Engines Branch CIVILIAN DEFENSE DIVISION 15 Bu.ssing XAG Flugmotorenwerke G m b H, Bruns- *40 Civilian Defen.se Division— Final Report wick, Germany 41 Cologne Field Rejwrt 1<> Mittel-Deufsche Molorenwerke G ni li II. Taucha, 42 Bona Field Report Germany 43 Hanover Field Report IT Bavarian Motor Works Inc. Eisenach & Durrerhof, 44 Hamburg Field Rei)ort— Vol I, Text; Vol Geimany Exhibits 18 Bayerische Molorenwerke A G (BMW) Munich, 45 Bad Oldesloe Field Report Germany 46 Augsburg Field Report 19 Henschel Flugmotorenwerke, Kas.sel, Germany 47 Keception Area in Bavaria, Germany 66 EQUIPMENT DIVISION Motor Vehicles and Tanks Branch Electrical Branch •77 German Motor Vehicles Industry Report *78 Tank Industry Report (icnuiiii lOU'ctricMl E(juipmoiit Industry Kcport 79 Daimler Benz A (J, Unterturkheim, Germany Hrowii Boveri et Cie, Mannheim Kafertal, Germany 80 Renault Motor Vehicles Plant, Billancourt, Paris 81 Adam Opel, Russelheim, (iermany Optical and Precision Instrument Branch 82 Daimler Benz-Gaggenau Works, Gaggenau, Gei'- iiptical and rrccisidii Iiislnnnont Industry Report ma ny 83 Maschinenfabrik Angsburg-Nurnberg, Nurnberg, Abrasives Branch Germany The Gornuin Abrasive Industry 84 Auto Union A G, Chemnitz and Zwickau, Germany .Mayer and Schmidt, Offenbach on Main, Germany 85 Henschel & Sohn, Kassel, Germany 86 Maybach Motor Works, Friedrich.shafen, Germany Anti-Friction Branch 87 Voigtlander, Ma.schinenfabrik A (J, Plauen, Ger- many riie German Anti-Friction Bearings Industry 88 Volkswagenwerke, B''allersleben, Germany Machine Tools Branch 89 Bussing NAG. Brunswick, Germany 90 Muehlenbau Industrie A G (Miag) Brunswick, Ger- Maelune Tools & Machinery as Capital Equipment many .Machine Tool Industry in Germany 91 Friedrich Krupp Grusonwerke, Magdeburg, Ger- I [erman Kolb Co., Cologne, Germany many I'ollet and Engelhard, Offenbach, Germany Submarine Branch Xaxos Union, Frankfort on Main, Germany 92 German Submarine Industry Report MILITARY ANALYSIS DIVISION 93 Maschinenfabrik Augsburg-Nurnberg A G, Augs- burg, Germany I'lie Defeat of the German Air Force 94 Blohm and Voss Shipyards, Hamburg, Germany \ Weapons (Crossbow) Campaign 95 Deutschewerke A G, Kiel, Germany Air Force Kate of Operation 96 Deutsche Schiff und Masehinenbau, Bremen, Ger- Weather Factors in Combat Bombardment Opera- many tions in the Theatre p]uroi)ean 97 Friedrich Krupp Germaniawerft, Kiel, Germany I'.iinibing Accuracy, Heavy and USAAF Medium 98 Howaldtswerke A G, Hamburg, Germany Bombers in the ETO 99 Submarine Assembly Shelter, Farge, Germany I icscription of RAF Bombing 100 Bremer Vulkan, Vegesack, Germany . The Impact of the Allied Air Effort on German Lo- gistics Ordnance Branch MORALE DIVISION *101 Ordnance Industry Report 102 Friedrich Krupp Gruisonwerke A G Magdeburg, iJ I he Kft'ects of Strategic Bombing on German Germany Morale (Vol I & II) 103 Bochumer Verein fuer Gu.sstahlfabrikation A G, Medical Branch Bochum, Germany 104 Henschel & Sohn, Kassel, Germany I i'lic Effect of Bombing on Health and Medical Care 105 Rheinmetall-Borsig, Dusseldorf, Germany in Germany 106 Hermann Goering Werke, Braunschweig, Hallen- dorf, Germany MUNITIONS DIVISION 107 Hannoverische Masehinenbau, Hanover, Germany Heavy Industry Branch 108 Gu.sstahlfabrik Friedrich Krupp, Essen, Germany 11 i'lie Coking Industry Rejwrt on Germany i OIL DIVISION Inking Plant Reixtrt No. 1, Sections A, B, C, & D - liiitehoffnung.shuette, Oberhausen, Germany *109 Oil Division, Final Report « Friedrich-Alfred Huette, Rheinhausen, Germany <110 Oil Division, Final Report, Appendix Xeunkirchen Eisenwerke A G, Neunkirchen, Ger- *111 Powder, Explosives, Special Rockets and Jet Pro- many pellants. War Gases and Smoke Acid (Ministerial 1 Ivfichswerke Hermann Goering A G, Hallendorf, Report #1) I iKiitmund Hoerder Huettenverein, A G, Dortmund, 114 Ministerial Report on Chemicals • ierniany •' Hiiesch A G, Dortmund, Germany Oil Branch «|Bocliunier Verein fuer Giisstahlfabrikation A G, 115 Ammoniakwerke Merseburg G ni b H, Leuna, Ger- Bochum, Germany numy—2 Appendices 67 110 Iii:iniiki)hle Benzin A G, Zeitz and Boblen, Ger- 147 Gnome et Rhone Aero Engine Factory, Le Ma iiKiiiy, Wintersliall A G, Leiifzkendorf, Germany France 117 Ludwigsliafen-Oiipini Works of I G Farbenindustrio 148 Kugelfischer Bearing Ball Plant, EbeLsbach, G A G, Ludwig.shafen, Germany many lis Ruhroel Hydrogenation Plant, Bottroi»-r.oy, Ger- 149 Louis Breguet Aircraft Plant, Toulouse, France many. Vol. I, Vol. II 150 S. N. C. A. S. E. Aircraft Plant, Toulouse, Fran 119 Rhenanla Ossag Mincraloclwerke A G, Ilarlmrg 1.51 A. I. A. Aircraft Plant, Toulouse, France Refinery, Hamburg. Germany 152 V Weapons in London 120 Rhenauia Ossag Mineraloelwerke A G, Grasbrook 153 City Area of Krefeld Refinery, Hamburg, Germany 1.54 Public Air Raid Shelters in Germany 121 Rhenania Ossag Mineraloelwerke A G, Willielms- 1.55 Goldenberg Thermal Electric Power Station, Kb burg Refinery. Hamlinrg. Germany sack, Germany 122 Gewerkschaft Victor, Castrop-Rauxel, Germany, 1.5C Brauweiler Tran.sformer & Switching Stat Vol. I & Vol. II P.rauweiler, Germany 123 Europaeische Tanklager nnil Transport A G, Ham- 157 Storage Depot, Nahbollenbacli. Germany burg, Germany 158 Railway and Road Bridge. Bad Mnnster, Germ. 124 Ebano Asphalt Werke A G, Harburg Refinery, 159 Railway Bridge, Eller, Germany Hamburg. Germany IfiO Gustloff-Werke Weimar, Germany 125 Meerbeck Rbeinpreussen Synthetic Oil Plant—Vol. Kil Ilenschel & Sohn G ni b H. Ka.s.sel. Germany I & Vol. II 162 Area Survey at Pirmasens, Germany 163 Hanomag, Hanover, Germany Rubber Branch 164 M A N Werke Augsburg. Augsburg, Germany 165 Friedrich Krupp A G, Essen, Germany 12G Deutsche Dunlop Gummi Co., Hanau on Main. Germany 1116 Erla Mascliincnwerke. (i ni b H. Heitcrblick, ( li. 127 Continental Gumniinerke. Hanover, Germany many 167 Maschinenbau H, Mockau, Germ 128 Huels Synthetic Rubber Plant A T G G m b 168 Erla Maschinenwerke G m h H, Mockau, Germ 129 Ministerial Report on German Rubber Industry 169 Bayerische Motorenwerke, Durrerhof, Germar 170 Mittel-Deutsche Motorenwerke G m 1) H, Taui Propellants Branch Germany 1.30 Elcktrochemischewerke, Munich, Germany 171 Submarine Pens Deut.sche-Werft, Hamburg, ( 131 Scboenebeck Explosive Plant, Lignose SprengstofC many Werke GmbH, Bad Salzemen, Germany 172 Multi-Storied Structures, Hamburg, Germany 132 Plants of Dynamit A G, Vormal, Alfred Nobel & 173 Continental Gummiwerke, Hanover, Germany Co, Troisdorf, Clausthal, Drnmmel and Dune- 174 Kassel Marshalling Yards, Kassel, Germany berg, German.v 175 Amnioniawerke, Merseburg, Leuna, Germany 133 Deut.scbe Sprcngcbemie G m b II, Kraiburg, Ger- 176 Brown Boveri et Cie, Mannheim, Kafertal, ' many m:iny 177 Adam Opel A G, Rnsselsheim, Germany OVERALL ECONOMIC EFFECTS DIVISION 178 Dainder-Benz A. G, Interturkheim, Germany 179 ^'alentin Submarine Assendily, Fargc, German' V.U Over-all Economic Effects Division Report 180 Volkswaggonwerke, Fallerslebeu, Germany Gross National Product Special pai>ers 181 Railway Viaduct at Bielefeld, Germany Kriegseilberichte . which together 182 Ship Yards Howaldtswerke, Hamburg, Germai Hermann Goering Works comprise the 183 Blolim and Voss Shipyards, Hamburg, German Food and Agriculture above report 184 Daimler-Benz A. G, Mannheim, Germany 134a Industrial Sales Output and Productivity 185 Synthetic Oil I'lant. Mcerbeck-IIambui'g. Germt li- 186 Gewerk.schaft Victor, Castrop-Rauxel, German PHYSICAL DAMAGE DIVISION 187 Klockuer Humboldt Deutz, Ulm, Germany 188 Ruhroel Hy.drogenation Plant, Bottrop-Boy, (r 134b Physical Damage Division Report (ETO) many 133 Villaconlilay Airdrome, Paris. France 189 Neukirchen Eisenwerke A G, Neukirchen, Germ f 136 Railroad Repair Yards, Malines. Belgium 190 Railway Viaduct at Altenbecken, Germany 137 Railroad Repair Yards, Louvain, Belgium 191 Railway Viaduct at Arnsburg, Germany 138 Railroad Ripair Yards, Hasselt, Belgium 192 Denrag-Nerag Refineries, Misburg, Germany 139 Itailroad Repair Yards, Namur, Belgium 193 Fire Raids on German Cities 140 Suliniarinc I Pens, Brest, France 194 I (i Farbenindustrie, Ludwigshafen, Germany. 141 Powder I'lant, Angouleme. France I & Vol II 142 Powder Plant, Bergerac, France 195 Roundhouse in Marshalling Yard, Ulm, Genuiii 143 Coking Plants, Montigny & Liege, Belgium 190 I G Farbenindustrie, Leverkusen. Germany 144 Fort St. Blaise Verdun Group, Metz, France 197 Chemische-Werke, Heuls, Germany 14.J Gnome et Rhone, Limoges, France 198 Grcndierg Marshalling Yard, Grenilierg, Germil' 140 MIchelin Tire Factory, Clcrmont-Ferraiid, Franc 199 Locomotive Sliups and P.ridges at Ilaiinn, Germi'' es ) TRANSPORTATION DIVISION *17 Nakajima Aircraft Company, Lid. Corporation liepurt A'o. // I I'.oinliiiiK uii (ici-many 'I'lic EllVcls of Sti-:ilryic (Nakajima Hikok KK) 'I'vausiKivtatidii (Airframes & Engines) ( i;.iil Operations Ovci- llif Itrcniicr I'ass *18 Kawanishi Aircraft Company I i:rr('cls of Bombing on Kailroad Insfallatioiis in i'orporation licjiort Ao. /// Ito^'enslnng, Nurnljerg and Miniicli Divisions. (Kawanislii KokiiUi Kiibusblki Kaislia) German Locomotive Industry During the War (Airframes) German Military Ttailroad Tratlie *19 Kawasaki Airei'aft Industries Company, Inc. UTILITIES DIVISION C'orporaiio)! Hiport .\o. IV (Kawasaki Kokuki Kogyo Kabushiki German Electric Utilities Industry Report Kaisha I to 10 in Vol I "Utilities Division Plant Reports"' (Airframes & Engines) II to 20 in Vol II "Utilities Divisi(m Plant Re- *20 Aiclii Aircraft Comi)any ports" CorponitioH Report Xo. V '21 Klieiniselie-Westfalisclie Elektrizitaetswerk A G (Aichi Kokuki KK) (Airframes & Engines) Pacific War *21 Sumitomo Metal Industries, Proijeller Divi-sion OFFICE OF THE CHAIRMAN Corporation Report Xo. VI (Sumitomo Kinzoku K(isyci KK, Pnropera Summary Report (Pacific War) Seizosho) Japan's Struggle to End The War ( Propellers 1 The Effects of Atomic Bombs mi llirnsliima and *22 Hitachi Aircraft Company Nagasaki Corporation Report Xo. VII CIVILIAN STUDIES (Hitachi Kokuki KK) (Airframes «& Engines) Civilian Defense Division *2;^ Japan International Air Industries, Ltd. Field Report Covering Air Raid Protection and Corporation Report Xo. VIII Allied Subjects, Tokyo. Japan (Nippon Kokusai Koku Kogyo KK) Field Report Covering Air Raid Protection and (Airframes) Allied Subjects, Nagasaki, Japan Field Report Covering Air Raid Protection and *24 Japan Musical Instrument Manufacturing Com- Allied Subjects, Kyoto, Japan pany Field Report Covering Air Raid Protection and Corporation Report Xo. IX Allied Subjects, Kobe, Japan (Nippon Gakki Seizo KK) Field Report Covering Air Raid Protection and (Propellers) Allied Subjects, Osaka, Japan *2."> Tacbikawa Aircraft Company Field Report Covering Air Raid Protection and Corporation Report Xo. X Allied Subjects, Hiroshima, Japan—No. 1 (Tacbikawa Hikoki KK) Summary Report Covering Air Raid I'rotection (Airframes) and Allied Subjects in Japan *2('i Fuji Airplane Company Final Report Covering Air Raid Protection and Corporation Report Xo. XI Allied Subjects in Japan (Fuji Hikoki KK) (Airframes I Medical Division *27 Shdwa Airplane Company The Effects of Bombing on Health and Medical Corporation Report Vo. XII Services in .Japan (Showa Hikoki Kogyo KK) The Effects of Atomic Bombs on Health and Med- (Airframes) ical Services in Hiroshima and Nagasaki *2S Lshikawajima Aircraft Industries Company, Ltd. Report No. Morale Division Corporation XIII (lshikawajima Koku Kogyo Kabushiki The Effects of Strategic Bombing on Japanese (Kaisha) rale (Engines) ECONOMIC STUDIES *20 Nippon Airplane Company Corporation Report Xo. XIV Aircraft Division (Nippon Hikoki KK) 5 The Japanese Aircraft Industry (Airframes) 'J Mitsubishi Heavy Industries, Ltd. *30 Kyushu Airplane Comiiany Corporation Report No. I Corporation Report No. XV (Mitsubishi Jukogyo KK) (Kyushu Hikoki KK) (Airframes & Engines) (Airframes) 69 ) Urban Areas Division *31 Shoda Engineering Company Corporation Rvvort No. XVI Effects of Air Attack on Japanese Urban Econ (Slioda Seisakujo) (Summary Report) (Comiwneuts) Effects of Air Attack on Ihban Complex To •32 Mitaka Aircraft Inilustries Kawasaki-Yokohama Corporation Heport A'o xrii Effects of Air Attack on the City of Nagoya (Mitaka Kokvi Kngyo Kaluisliiki Kaislia) Effects of Air Attack on Osaka-Kobe-Kyoto ( ('uuii)iinents) Effects of Air Attack on the City of Nagasaki 33 Nissan Aiitonioliile Company 60 Effects of Air Attack on the City of Hiroshim Corporation Rvport Xo. XVIII (Nissan Jidoslia KK MILITARY STUDIES (Engines) Military Analysis Division »34 Army Air Arsenal & Xavy Air Depots United States in Corporation Report No. XIX 61 Air Forces Allied with the (Airframes and Engines) W^ar Against Japan *35 Underground Production of Japanese Aircraft 62 Japanese Air Power Report Xo. XX 63 Japanese Air Weapons and Tactics 64 The Effect of Air Action on Japanese Gr Basic Materials Division Army Logistics 65 Employment of Forces Under the South •30 Coal and Metals in Japan's War Ecouomy I'acitic Command 06 The Strategic Air Ol>erations of Very H Capital Goods, Equipment and Construction Division Bombardment in the War Against J *37 The Japanese Construction Industry (Twentieth Air Force) *38 Japanese Electrical Equipment 07 Air Operations in China, Burma, India—"V *39 The Japanese Machine Building Industry War II OS The Air Transport Command in the War Ag Electric Power Division Japan 09 The Thirteenth Air Force in the War Ag *40 The Electric Power Industry of Japan Japan •41 The Electric Power Industry of Japan (Plant Re- Seventh and Eleventh Air Forces in the ports) 70 The Against Japan Manpower, Food and Civilian Supplies Division 71 The Fifth Air Force in the War Against Japi *42 The Japanese Wartime Standard of Living and Naval Analysis Division Utilization of Manpower *72 The Interrogations of Japanese Officials (V' and II) Military Supplies Division *73 Campaigns of the Pacific War •43 Japanese War Production Industries *74 The Reduction of Wake Island •44 Japanese Naval Ordnance *75 The Allied Campaign Against Rabaul 45 Japanese Army Ordnance 76 The American Campaign Against Wotje, 1 *46 Japanese Naval Shipbuilding lap, Mille, and Jaluit (Vols. I, II and III) •47 Japanese Motor Vehicle Industry *77 The Reduction of Truk •48 Jai>anese Merchant Shipbuilding 78 The Offensive Mine Laying Campaign Af Japan Oil and Chemical Division 79 Reiwrt of Ships Bombardment Survey Pa Foreword, Introduction, Conclusions, and 49 Chemicals in Japan's War eral Summary 50 Chemicals in Japan's War—Appendix 80 Report of Ships Bombardment Survey Party 51 Oil in Japan's War closure A), Kamaishi Area 52 Oil in Japan's War—Appendix 81 Reiwrt of Ships Bombardment Survey Party 5l Over-all Economic Effects Division closure B), Hamamatsu Area 82 Report of Ships Bombardment Survey Party 5) •53 on Japan's War The Effects of Strategic Bombing closure C), Hitachi Area (Including Appendix A: U. S. Eco- Economy 83 Report of Ships Bombardment Survey Partj Analysis and Com- nomic Intelligence on Japan— closure D), Hakodate Area Appendix B: Gross National Product IKirison; 84 Report of Ships Bombardment Survey rart.\ on and Its Cunipononts; Appendix C: Japan closure E), Muroran Area Statistical Sources). 85 Report of Ships Bombardment Survey Parlj closure F), Shimizu Area Transportation Division '"' 86 Report of Ships Bombardment Survey Party NoM •M The War Against Japanese Transportation, 1941- closures G and II), Shionomi-Saki and 1945 Saki Areas 70 IJipori (it' Ships I!oiMli:ir(liiii'iil Survey I'lirly (Kii- !>.S iliiMiri' I I, ( '(Uiiinc'iils ;iii(l l):il:i on Kft'i'ctivciiess nl' AllllllUIlitidll 1;^ port (if Ships Bdiiiliardiiiciil Siii'vcy I'afty (Eii- ( IdSiire .1). ('(iiiiinciils Mild Unta (in Accuracy of I'ii'iii:;- Kipdi-ts (if Ships P.oiiilianliiK'iit Survey I'arty (Eii- I Insure K), lOffects (if Surface Kdiiiliariliiii'iits on .la]>aiiese War I'oleiitial Physical Damage Division Kffect of llie Incendiary Bonili Atta(ks on Japan (a Heiiort on Eight Cities I The EfftH-t.s of the Ten Thousan Effects of the Four Thousand round Bomii (ni Japanese Targets (a Keiiort on Five Incidents) Effects of Two Thousand, One Thousand, and Five Hundred Pound Bombs on Japnne.se Targets (a Iteport on Eight Incidents) i. Itejiort on Ph.vsical Damage in J.ipan (Sum- mary I!ei>ort) G-2 Division lapanese Military and Naval Intelligence ^'\o 'bO I no 3 \ s i£> '5 3