Chapter IV

1. Juyo Shorui Tsuzurt (File of Important Documents) Preserved by Capt. Toshikazu Ohmae, member, A Military Affairs Bureau, Navy Ministry. All source materials cited in this chapter are located in G-2 Historical Section Files, GHQ FEC.

2. Cf. section on Shipping.

3. Jinko Tokei Soran (General Compilation of Statistics on Population) Population Branch, Welfare Ministry Research Institute. Sep 43, pp. 2-3.

4. Memorandum Report submitted by Lt. Gen. (ret.) Teiichi Suzuki, President of the Planning Board, at the Imperial conference of 5 Nov 41. Preserved in the Notes of Maj. Gen. Kikusaburo Okada, Chief of War Plans Section, Economic Mobilization Bureau, War Ministry.

5. Ibid.

6. Ibid.

7. Ibid.

8. Extract from report of Chief of Staff of Izeki Force, North China, 25 August 1941: "Due to the present international situation and the increase in national military preparations, the importace of exploiting and utilizing the resources of this area must be considered. The accumulation of these military supplies will be subdivided into procurement by military authorities and purchases by civilian agencies. The items to be acquired by civilians are copper ore, copper wire scrap, copper scrap, brass scrap, cases, melted cases, tin, coin, pewter, and antimony ore.

"Scrap iron in North China will be acquired by the Nippon Iron Industries Company. Other resources to be acquired are nickel, cobalt, tungsten ore, molybdenum ore, copper, lead, zinc, quicksilver, high grade asbestos, high grade mica, nonferrous metals, steel, and other minerals.

"An investigation squad organized by the army has reported the probable presence zinc in the vicinity of Yancheng and of iron in Suehchuanling." ATIS Bulletin No. 1555, 5 Nov 44.

9. Notes of Maj. Gen. Okada, op. cit.

10. Ibid.

11. Statement by Maj. Gen. Okada, previously cited.

12. Notes of Maj. Gen. Okada, op. cit.

13. Ibid.

14. Ibid.

15. Statement by Capt. Toshikazu Ohmae, Chief, Operations Section, Imperial General Headquarters, Navy Section, and Col. Takushiro Hattori, Chief, Operations Section, Imperial General Headquarters, Army Section.

16. Data regarding Imperial General Headquarters decision on areas to be occupied furnished by Rear Adm. Sadatoshi Tomioka, Chief, First Bureau (Operations), Imperial General Headquarters, Navy Section, and Col. Hattori, previously cited.

17. Post-war interrogations of former Japanese military and naval leaders conclusively establish the vital strategic importance of the Philippines in Japan's 1941 war planning.

(1) The Japanese Navy, which already had plans for Pearl Harbor, felt that it was necessary to attack the Philippines at the same time to insure the success of our operations. The Navy felt that war with the United States was inevitable, and that to by-pass the Philippines would seriously hamper naval operations. The Philippines were a distinct threat as a base on the Navy's flank."   Interrogation of General Hideki Tojo, Premier and War Minister 1941-4.

(2) The Philippines were included within the scope of operations in the southern area because of their strategic importance and not for any political or economic reason. During the first half of 1941 when the Southern operations were being studied, the Army and Navy did not at first agree on the inclusion of the Philippines in the invasion plans. As a result of joint research conducted by the Operations Sections of the Army and Navy, the Army agreed to invade the Philippines at the beginning of the war. (Statement by Col. Hattori, previously cited).

(3) In all planning, taking the Philippines was considered imperative because of their strategic position as an American base. The Navy planned to take the Philippines in order to eliminate the United States naval base there, thus forcing the United States Navy to operate from far distant bases. The Philippines lay athwart the line of communications to the south, and it was necessary to remove this threat. It was military common sense that the Philippines had to be taken in the initial attack. The Philippines were an economic burden to Japan. The Planning Board knew this in advance. Nor wre there any political motives for the Philippines attack. It was purely for strategic military reasons... to eliminate the threat of American advance bases on the Japanese line of communications to the southern regions of Indonesia, Malaya, etc. Statement by Rear Adm. Tomioka, previously cited.

18. Statements by Col. Ichiji Sugita, Staff Officer (Intelligence), Imperial General Headquarters, Army Section, and Rear Adm. Tomioka and Col. Hattori previously cited.

19. Section on "Timing of the Attack" is based on data prepared by Rear Adm. Tomioka and Col. Hattori, previously cited.

20. The Japanese correctly appraised the social and convivial implications of the American "week-end".

21. Cf. Chapter III.

22. Cf. Chapter III.

23. Material in this section is based on statements by Rear Adm. Katsuhei Nakamura, Senior Adjutant of Navy Ministry, and Col. Hattori, previously cited.

24. The Liaison conference convened only when necessary until November 1940, when meetings began to be held twice weekly at the Premier's official residence. In July of the following year, after Germany invaded Russia, the members agreed to make more active use of the Council, and the meeting place was then changed to the Imperial Palace. Following the establishment of the Koiso Cabinet in July 1944, the Council was newly designated the "Supreme War Direction Council," but its functions remained unchanged.


Growth of Army and Navy Forces

Army2 Navy3
Year Fighters Bombers Rcn Total Carrier Based Fighters Land Based Bombers Torpedo Planes Other Types Total
1935 * * * * 188 108 24 132 138 590
1936 * * * * 216 120 144 132 160 772
1937 210 210 120 540 216 132 204 108 178 838
1938 240 330 130 700 269 132 228 132 200 961
1939 280 450 180 910 201 132 288 156 228 1,005
1940 360 500 200 1,060 167 132 264 180 306 1,049
8 Dec 1941 550 660 290 1,500 684 252 443 92 198 1,669

1. Statistics include only first-line aircraft
2. Compiled by 1st Demobilization Bureau, Japanese Government
3. Compiled by 1st Demobilization Bureau, Japanese Government
* Figures not available

26. From a strength of 17 divisions (not including 13 reserve divisions) during the period 1924-36, the Army expanded as follows:

Year No. of Divisions
1937 24 (Not including 6 reserve divs.)
1938 34
1939 41
1940 50
1941 51
(Statistics compiled by the 1st Demobilization Bureau, Japanese Government)

27. Statistics compiled by the 2d Demobilization Bureau, Japanese Government

Chapter IV

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Last updated 1 November 2006