CHAPTER I
PRE-WAR JAPANESE MILITARY PREPARATIONS 1941

Summary

By 5 November 1941 the Imperial Japanese Government had positively committed itself to taking up arms against the United States, Great Britain, and the Netherlands if, by the first part of December, no diplomatic solution of the Pacific crisis appeared attainable.¹This formal decision was made at the Imperial conference of 5 November, 17 days after the formation of the Tojo Cabinet.²

At this date Japan's military preparations for war were already far advanced. The Imperial conference of 6 September, in view of the unpromising outlook of negotiations with the United States, had decided that such preparations be rushed to completion by the end of October. Under that decision steps were taken to mobilize shipping for Army and Navy use, and the Army began assembling its invasion forces in Japan Proper, Formosa, and South China.³

The idea of a surprise attack on Pearl Harbor in the event of war was initially conceived by Admiral Isoroku Yamamoto, Commander-in-Chief of the Combined Fleet, in January 1941.⁴ From June of the same year, as Navy leaders became more convinced that their strategy must be based on the hypothesis of fighting the United States and Britain simultaneously, Admiral Yamamoto actively pressed his plan against the opposition of some members of the Navy General Staff, and it was finally accepted in principle on 20 October.⁵

At the annual Navy war-games, held in Tokyo from 10 to 13 September, the general problem under study was fleet operations to establish Japanese control of the Western Pacific, assuming the United States, Britain, and the Netherlands as enemies. The war-games were conducted on the hypothesis of a sortie by the main body of the American fleet into the Western Pacific to block Japanese invasion operations against the Philippines, Malaya, and the Dutch East Indies. However, a special, restricted group of high-ranking staff officers simultaneously studied problems involved in a surprise task force strike at Pearl Harbor.⁶

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By 3 November the basic plan for all naval operations attendant upon the commencement of hostilities had been agreed upon and was embodied in Combined Fleet Top Secret Operations Order No. 1, issued on 5 November. Two days later Combined Fleet Top Secret Operations Order No. 2 designated 8 December⁷ as the approximate date of the opening of hostilities (Y-Day), and units of the Pearl Harbor Task Force were simultaneously ordered to assemble in Tankan Bay by 22 November. The definitive date for the start of war (X-Day) was not fixed until 2 December, when the Task Force was already well on its way to Hawaii. A Combined Fleet order issued at approximately 5:30 p.m. on that date designated 8 December as X-Day.⁸

Final Army preparations were also completed during November. Imperial General Headquarters on 6 November established the order of battle of the Southern Army under over-all command of General Hisaichi Terauchi, and on 15 November designated the Philippines, British Malaya, the Dutch East Indies, and part of Southern Burma as the areas to be occupied. Invasion assignments were made to the various forces under Southern Army command on 20 November.⁹

Army and Navy operational plans were coordinated through an Army-Navy Central Agreement concluded in Tokyo on 10 November between General Terauchi, Commander-in­Chief of the Southern Army, and Admiral Yamamoto, Commander-in-Chief of the Combined Fleet. This basic document, which defined the relative commands, spheres of jurisdiction, missions, and responsibilities of the two services in all areas where joint operations were envisaged, was supplemented by detailed operational agreements concluded in mid-November between the Fleet and Army commanders assigned to each area.

The Japanese military authorities were both far-sighted and thorough in certain of their preparations for the war. Selected units were given specialized training in jungle warfare and amphibious operations; secret agents were dispatched to future zones of operation for purposes of espionage and reconnaissance; maps of crucial areas were prepared far in advance; morale and training literature was written and distributed to units; special striking forces were organized, equipped with tropical issue, and staged to carefully selected assembly areas where a maximum of security was assured; and the necessary transport and convoy facilities were arranged in advance.

Official unit reports refer to the periods 27 July - 7 December 1941, 12 October - 14 November 1941, and 10 October - 8 December 1941 as having been devoted to preparation for the Philippine and Malayan Operations. Units receiving this training were currently in Manchuria, the vicinity of Shanghai, and at Palau.

By 10 November 1941, copies of a pamphlet entitled, "Read This and the War is Won," had been received by 55th Division Infantry Group.¹⁰ The text was clearly premonitory of the imminence of war with the

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The significantly named South Seas Detachment was already organized, on paper at least, by 15 November 1941. It comprised the force which took Guam on 10 December and later moved on to Rabaul and New Guinea.¹¹

On 15 November, the Commanding General of the South Seas Detachment, Maj. Gen. Tomitaro Horii, issued a "Message to Warriors in the South Seas," addressed to all personnel serving under his command. This message forecasted with great explicitness the coming of war. No date of outbreak was mentioned, but the tenor of the communication was that of a commander to his troops on the eve of battle.

Certain elements of the newly formed South Seas Detachment were being routed to a staging area in Japan as early as 14 November 1941. A part of the 47th Antiaircraft Battalion, for example, left its station in Manchuria and was transported to the port of Sakaide in Northern Shikoku, via Pusan and Ujina. A major portion of the South Seas Detachment appears to have rendezvoused there. On 22, 23, and 24 November, various units embarked and departed for the Ogasawara (Bonin) Islands. The transports arrived at their destination on 27 November 1941, some touching briefly at Chichi-Jima en route to Haha-Jima. At Haha­Jima the troops rested and trained. On 4 December, the convoy sailed to carry out the attack on Guam.

On 29 November 1941, at 1500 hours, 1st Lt. Sakigawa, Commanding Officer of 2nd Company, 55th Transport Regiment, issued Saki Operation Order No. 2. This read in part, " The Detachment will attack Guam Island."

The mounting of the attack on British Malaya has been partially reconstructed from official documents and diaries deriving from the 41st Infantry Regiment, 106th Land Duty Company, Sasebo 5th Special Naval Landing Party, and 77th Air Regiment, elements of all of which participated in the operation.

On 17 November 1941, 41st Infantry Regiment, which had been stationed in the vicinity of Shanghai since at least early October, training for the Malayan Operations, held a review and ceremony in honor of their "departure for the field". On 18 November, elements of the regiment left Shanghai on the Ryujo Maru for the assembly point at Samah, on the southern shore of Hainan Island.  The diary of one member contained the following entry under date of 18 November: "...... orders have finally arrived.  The time has finally come for us to display activity. Are we going to be at war with A, B and D?" On 21 November the Ryujo Maru was anchored at Takao. Its date of arrival at Samah is not known, but other elements of the regiment had reached Haikow in Northern Hainan by 20 November. On the same date further elements of the regiment embarked on the Aobayama Maru and on 21-22 November sailed from Woosung for Samah.  Part of the 106th Land Duty Company left Saigon on the Tokokawa Maru on 23 November and arrived at Samah on 25 November. On 25 November also, elements of Sasebo 5th Special Naval Landing Party, while en route to Palau, were ordered to change course and head for Samah.  A second section of the 106th Land Duty Company embarked on the Taikai Maru at Saigon on 27 November

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Preparations for the eventual conquest of the Philippines date farther back. There is evidence of extensive prewar aerial reconnaissance of northern Luzon during the period 27 November to 15 December 1940.¹² (Plate No. 2 shows the photographic coverage obtained and the dates on which the flights were carried out.)

Other evidence indicates that the training of units earmarked for participation in the Philippines campaign was probably under way by early fall of 1941. An extract from Fourth Air Army Ordnance Order No. 12, dated 26 March 1944, reads

Death certificate and service record of Sergeant Takeo Goto:
Unit: 25th Water Purification Unit.
Year of conscription: 1939  
Service: 27 July 1941 to 7 December 1941, Manchurian Border Defense and preparation for the Philippines operations.¹³

The main lines of the operational plan for the Philippines invasion were worked out at the joint Army-Navy staff conference held at Iwakuni, on the Inland Sea, from 14 to 16 November. Orders were issued on 20 November to Fourteenth Army units in Formosa directing them to concentrate at the assembly points in readiness for embarkation.¹⁴

The Tanaka Detachment, one of the advance forces which landed at Aparri and Vigan, on northern Luzon, embarked at Takao between 23 and 25 November and moved to the naval port of Mako, in the Pescadores, which had been fixed as the starting point of the advance invasion convoy. This force and the Kanno Detachment (Vigan landing) remained at Mako until 1700 on 7 December, when the convoy sailed for northern Luzon.¹⁵

On 16 November and 26 November respectively, the commanders of the heavy cruiser Kako and the light cruiser Katori addressed their crews in terms clearly indicative of the imminence of war. On the latter date also, Vice Adm. Chuichi Nagumo informed some of the personnel of the task force assembled at Tankan Bay that they were to attack Pearl Harbor.

Various individuals displayed advance knowledge or suspicion of the imminence of war. It is not certain in some cases whether this was based on information derived from reliable official sources or from rumor and popular gossip. Nevertheless, as early as October 1941, the rumor was current on Truk that war would break out with the United States between 25 December 1941 and 1 February 1942. On 18 November, a member of the 41st Infantry Regiment commented on the probable imminence of war with "A, B and D." On 26 November, a member of the 144th Infantry Regiment, South Seas Detachment, wrote, "Our battle zone will be Guam Island." Two other members of the South Seas Detachment displayed similar knowledge of impending hostilities on 29 November.

Between 2-7 December knowledge of the scheduled outbreak of hostilities on 8 December became quite general among members of stri­

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On 1 and 3 December orders for the air defense of Keelung and Samah respectively were issued by the 48th Field Antiaircraft Battalion and 77th Air Regiment. These clearly anticipated the possibility of enemy air attacks.

The evidence upon which the foregoing summary is based is further amplified in the following paragraphs. References have been arranged chronologically in accordance with the date of the most significant entry contained in the diary or other captured document under examination.

Pearl Harbor Planning (Jan.-Nov. 1941)

When Japanese planes struck immobile United States warships and aircraft at Pearl Harbor on 8 December 1941, they were executing pinpointed plans conceived months in advance and cloaked in the utmost secrecy. Authoritative Japanese documents obtained since the termination of war and interrogations of the high naval personnel who participated in or had knowledge of this planning make it possible to reconstruct a complete and accurate picture of how the Pearl Harbor attack was conceived and developed over an eight-month period preceding the final outbreak of hostilities.

Prior to 1941 Japanese naval planning for a possible war with the United States had been based upon the assumption that the latter would be Japan's only enemy, and it envisaged awaiting attack by the American fleet in the Western Pacific where Japan's numerically inferior fleet could operate at an advantage.¹⁶ By the end of 1940, however, Japan's entry into the Tripartite Alliance and the United States' aid commitments to Britain had created a new international line-up which made previous Japanese naval planning obsolete. The Japanese Navy began to plan for a simultaneous war against the United States and Britain.

The idea of a surprise attack on Pearl Harbor at the outset of war, with the object of gaining at least temporary naval supremacy in the Western Pacific, was first conceived in early January 1941 by Admiral Yamamoto, Commander-in-Chief of the Japanese Combined Fleet. Admiral Yamamoto at that time ordered Rear Adm. Takijiro Onishi, chief of staff of the Eleventh Air Fleet, to study the feasibility of such an attack.¹⁷

On the basis of this preliminary study, Admiral Yamamoto in June 1941 began actively pressing for the adoption of his plan by the Navy General Staff as part of Japan's naval strategy in the event of war. Crippling the United States fleet at Hawaii at the start of hostilities, he argued, was absolutely essential to place the Western Pacific under Japanese control for the period necessary to complete the occupation of the strategic areas and economic resources of the South. Were Ame-

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Despite Admiral Yamamoto's arguments, his plan was vigorously opposed by a section of the Navy General Staff on the ground that swift occupation of the Southern areas was the prime necessity, and that this might fail if Japanese naval strength were divided between operations against Hawaii and support of the Southern invasions. It was further pointed out that detection of the Japanese force en route to Hawaii might result in its complete destruction, and that, even if this did not occur, the attack would be ineffectual if the bulk of the United States fleet was not caught in Pearl Harbor.¹⁹

This disagreement in the Navy High Command had not been resolved by 10 September, when staff officers of all fleet units assembled at the Naval War College in Tokyo for the annual Navy war games. Just four days earlier the Imperial conference of 6 September had debated the issue of war or peace in a dramatic session and had decided that Japanese military preparations must be speedily brought to completion. ²⁰ The games therefore took place amidst an atmosphere of unusual tension, further heightened by the fact that the central problem of study assumed an American fleet attack into the Western Pacific as a result of Japanese invasion operations in the Southern area.²¹

Admiral Yamamoto himself planned and exercised over-all supervision of the games. A general study session, including chart maneuvers participated in by all officers in tactical command of fleet units, occupied the first three days–10, 11, and 12 September. The last day, 13 September, was devoted to a special study session. Thirteen umpires headed by Rear Adm. Seiichi Ito, Vice-Chief of Navy General Staff, ruled on the execution of maneuvers. The Japanese (Blue) Forces were under command of Rear Adm. Matomi Ugaki, Chief of Staff of the Combined Fleet, and the British-American (Red) Forces under command of Vice Adm. Shiro Takasu, First Fleet Commander.

While the principal games were conducted on the old hypothesis of meeting an American fleet attack in the Western Pacific, a restricted group of staff officers of the Combined Fleet and commanders of those fleet units which eventually made up the Pearl Harbor Task Force²² met in a separate and top-secret session, the purpose of which was to study problems connected with a possible surprise attack on Pearl Harbor. These problems included:

1. Feasibility of an attack if (as estimated)

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only 50 per cent of American Pacific Fleet strength were in harbor.
2. The possibility of detection by American search planes before the attack could be executed.
3. The refueling at sea of Task Force units with inadequate cruising range.

The conclusions reached with regard to the solution of these problems were those later embodied in the actual operational plan and carried out in the Task Force attack.²³ However, it was not until 20 October, after Admiral Yamamoto had threatened to resign over the issue, that Admiral Osami Nagano, Chief of Navy General Staff, approved the Pearl Harbor plan in principle over General Staff opposition. Preparation of the detailed attack plan was completed during October and finally sanctioned by Admiral Nagano on 3 November.²⁴ In order to preserve secrecy, knowledge of the plan in its entirety was limited to the Chief and Vice-Chief of the Navy General Staff, the Chief and members of the Operations Section, Navy General Staff, Commander-in­Chief, Chief of Staff, and most staff officers of the Combined Fleet, First Air Fleet and Sixth Fleet.²⁵ Evidence indicates that Army leaders were not informed until sometime in November, following the issue of Combined Fleet Top Secret Operations Order No. 1.²⁶

Even in this order, issued on 5 November, the missions of the Advance (Submarine) Force and the Task Force which were to participate in the Pearl Harbor attack were left blank in the printed text, and the missing portions were communicated verbally only to those listed in the preceding paragraph.²⁷ The commanders of the Task Force units, which assembled in Tankan Bay between 15 and 22 November, were not informed of the attack plan until Vice Adm. Nagumo, commanding the Force, issued Task Force Top Secret Operations Order No. 1 on 23 November, three days before departure for Hawaiian waters.²⁸ Crew members were told that Pearl Harbor was the target only after receipt of the Combined Fleet X-Day order on 2 December.²⁹

October 1941

Prisoner of war Iwataro Fusei, (JA 145118), a civilian laborer in naval employ present at Truk throughout October 1941, stated that:

When he was at Truk in October 1941, there were rumors that a war with the United States would start

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about 25 December 1941 at the earliest and 1 February 1942 at the latest. When he returned to Japan in November 1941, rumors of war were far less current than at Truk.³⁰

A "Report on Conditions" issued by Lt. Col. Ryuto, Commanding Officer of the 42d Anchorage Group, dated 15 June 1942, states:

Record of General Situation since Mobilization.
The mobilization order was issued on 12 September 1941. Organization from the Hiroshima Western District No. 2 Force was completed by 17 September. We left Ujina on 29 September, sailing to Osaka where 40th Sea Duty Company was attached to us. We left Osaka on 1 October and reached our destination at Palau on 10 October where we established an anchorage headquarters. Then we made preparations for the landing operations which were to accompany the War for Greater East Asia.³¹

Personal history register of Leading Pvt. Hisazo Kashino of the 41st Infantry Regiment, contains the following entries:

10 October 1941-Left Ningpo.

11 October-Landed at Shanghai.

12 October to 14 November-Prepared for Malayan operations in the vicinity of Shanghai.

22 November-Left Woosung, Shanghai.

8 December-Landed at Singora, Thailand.³²

November 1941

Diary belonging to an unknown member of the 41st Infantry Regiment contains the entries quoted below. This regiment participated in the attack on Malaya, which was mounted from the port of Samah on Hainan Island.

12 October 1941-Reached Woosung Pier and returned to Kiangwan Barracks.

23 October-Okabe Force was assembled and heard an address from the newly appointed brigade commander, Maj. Gen. Saburo Kawamura. There will be a general inspection of the three battalions tomorrow.

4 November-Jungle combat training for expected type warfare.

13 November-Received rations and other necessary items for tropical combat (medicines and clothing, etc).

20 November-Anchored off Haikow on Hainan Island....

2 December-Weighed anchor and sailed again for Samah.

15 December-Assisted by our guns and tanks, our unit was the first to enter Gubun Street. Capt. Omori, 1st Lt. Nikki, and 2nd Lt. Takahashi were killed. 1st Lts. Okano and Yanagizawa were wounded.³³

The pamphlet quoted below, entitled, "Read This and the War is Won," was to be issued to each Japanese soldier before he embarked for overseas. The frontispiece consists of a map of South China, French Indo­China, Thailand, Burma, the Federated Malay States, the Netherlands East Indies, and a small section of the Northwest Australian Coast. The date of publication of the pamphlet is not definitely known. A captured copy, however, was received by 55th Division Infantry Group on 10 November 1941. (Elements of 55th Division figured prominently in the attack on Guam in December 1941 and later in the Burma Campaign). Furthermore, its length and the nature of the contents indicate original preparation at a date considerably prior to this. Pertinent sections of this pamphlet are reproduced below:

What sort of place is the southern field of operations?

(1)   It is the treasury of the Orient which has been invaded by the white men of England, America,

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France, and Holland.

(2) One hundred million Orientals are being oppressed by three hundred thousand white men.

It amounts to this–these whites possess scores of Oriental slaves from the moment they are born. Is this the intention of God?

(3) It is a source of world supply of oil, rubber, tin, etc.

Rubber and tin are essential for military supplies, and for these valuable resources the southern countries are the richest in the East. The malevolence of England and America, who have prevented Japan's purchasing these materials by just means, is one of the reasons which necessitates the present military operations.

It is quite clear that the Netherlands East Indies and French Indo-China cannot oppose Japan alone, but with the support and threats of England and America they are showing hostility to Japan. The lack of oil and iron is Japan's weak point, but lack of rubber, tin, and tungsten is the weakest point of America. America's chief sources of supply of these are the South Seas and Southern China. If these could be stopped, it not only would enable Japan to obtain the much-wanted oil and tin but it would stick a knife into America's sorest spot. The essence of America's opposition to Japan's southward advance lies here.

(4) It is a land of perpetual summer.

Bananas and pineapples are plentiful all the year round; at the same time troublesome malaria-mosquitoes are everywhere. In the Java and Singapore areas motor roads have been developed everywhere, but there are many uncivilized places, jungles, and swamps where neither man nor animals pass.

Why must we fight and how must we fight?

(1) By the Imperial will for the peace of the Orient.

The Meiji Restoration saved Japan from invasion by foreign powers. The Showa Restoration, by complying with the Imperial will for the peace of the Orient, must rescue Asiatics from disputes amongst themselves and the invasion of the white race and return Asia to the Asiatics. Peace in Asia will ensue, and this will be followed by peace in the world being firmly established.

Japan is given a great mission to save Manchuria from the design of Soviet Russia, free China from exploitation by the English and Americans, and then aid the independence of Thailand, Annam, and the Philippines, thus to bring about the happiness of the natives of the South Seas and India. This is the spirit of equality and brotherhood.

(2) While destroying the enemy show compassion towards those without crime.

Understanding this war as one between races, we must enforce our just demands on the Europeans, excluding Germans and Italians, without extenuation.

(3) Is the enemy stronger than the Chinese Army?

Comparing the enemy with the Chinese Army, since the officers are Europeans and non-commissioned officers for the greater part natives, the spiritual unity throughout the Army is zero. It must be borne in mind that the number of airplanes, tanks, and guns is far superior to those of the Chinese Army. However, not only are these of old types but their users are weak soldiers, so they are not of much use.  Consequently, night attack is what the enemy fears most.

(4) We must be prepared for the war to be a prolonged affair and proceed with every preparation for a drawn-out conflict.

What course will the war follow?

Long voyage followed by landing operations.

All fields of operations are in the South Seas over a thousand miles from Formosa. Some places take a week to ten days to reach. This wide sea is crossed by convoys of several hundred warships and merchantmen. Looking back, our ancestors conquered this rough sea and carried on trade and fought with wooden sailing ships hundreds of years ago. After several days journey in the confines of shipboard, enemy resistance on the shores must be overcome and landings enforced.

What to do aboard ship:

The most important thing in landing operations is the maintenance of secrecy. If the enemy gets to know in advance where we plan to land, it will be very difficult.

There are many instances where a simple thing

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written in a letter has been the cause of the defeat of a whole Army, or where a word dropped over a glass of wine in a cafe just before departure has been the cause of secrets coming to the ears of spies.

Remember how the 47 Ronin kept their secret through such trials until they had avenged their Lord; encourage one another to do likewise.

There is a timely story of a soldier attached to a certain unit, who landed in Southern China during the present Incident, wrote a letter and dropped it in the sea, sealed in a bottle. The letter was carried by the tide to the coast of Korea.  Supposing the letter had reached Vladivostok-what would have been the consequence? Often a clue is caught by aircraft and submarines which are at sea to find out the movements of out transport ships. Care must be observed in the disposal of dirt and rubbish.

Battle:

(1)  Squalls, mist, and night are over all. Europeans are dandies, and delicate and cowardly. Therefore, rain, mist, and night attacks are the things they detest most.  They consider night suitable only for dances but not for fighting-we must take advantage of this.

(2) Unlike the Chinese soldiers, our present enemy may use gas.  If you cast aside your gas mask because of the torment of wearing it in the heat, the consequence may be serious.

Action in particular zones:

Action in swamps and paddy-fields
French Indochina and Thailand are, next to Japan, the chief rice-producing countries, and there are paddy-fields everywhere and large swamps here and there. When passing through these places, each soldier must use snowshoes (made of straw and sticks).

The present war is a war with Japan's rise or fall at stake. What is at the bottom of America's action of gradually prohibiting the export of oil and iron to Japan, as if to strangle her slowly by "silk-wool"? If they stopped these exports at once, Japan, in her desperation, might march into the South. If the export of the rubber and tin of the South are checked by Japan, America's own sufferings will be far greater than those of Japan, who is harassed for want of oil and ore. It has been the policy of America up to now not to anger Japan, though weakening her. Japan has waited too long– if Japan is patient any longer our aircraft, warships, and motor cars will not move. Five years have passed since the beginning of the China Incident. Over 1,000,000 comrades have exposed their bones on the continent. The arms of Chiang Kai-shek, which killed these comrades, were sold mostly by England and America. Both England and America are prejudiced against the solidarity of the Oriental races as something that stands in the way of their making the Orient their permanent colony and are concentrating every effort on letting Japan and China fight. Our allies, Germany and Italy, are continuing a battle of death in Europe against England, America, and Soviet Russia. America is already assisting England and is essentially participating in the war.  For the existence of Japan herself and her obligation to the Tripartite Alliance, not a minute longer must be endured. Japan is confronted with a great mission, bravely to put the last finishing blow, as representatives of the Oriental race, to their invasion of several hundred years. Our incomparable Navy is in full readiness and is infallible: 5-5-3 is the ratio in figures, but if spirit is added, it is 5-5-7. Moreover, half of the British Navy has been smashed by Germany. For the Navy, now is the best time. The Chungking Government's umbilical cord is joined to England and America. Unless this cord is severed soon, the Japan-China Incident will never be permanently settled. The total settlement of the holy war is the present war.  The spirits of over a hundred thousand warriors are guarding us. The mass for the dead comrades is to win this war.

Whilst showing our heartfelt thanks to the Navy, who, conquering thousands of miles of sea and removing enemy interception, are protecting us without sleep and rest, we must fully repay them for their trouble with good war results. We are privileged with an important and honorable mission to stand as representatives of the Asiatic race and to reverse the history of the world, succeeding our glorious history of 2,600 years and for the trust and reliance in us of His Majesty the Emperor.  Both rank and file with one mind must exhibit the real value of Japan's sons in this full-dress display watched by the whole world.

The completion of the Showa Restoration to free Asia in realization of the Imperial will, which is for peace in the East, rests on our shoulders.³⁴

The pamphlet entitled, "Message to Warriors in the South Seas," was issued on 15 November 1941 above the signature of Maj. Gen. Horii, Commanding General of the South Seas Detachment, which comprised the main force in the attack on Guam.³⁵

RESTRICTED
A Guide for Warriors in
The South Seas

South Seas Detachment Hqs.
15 November 1941

Horii Force Staff -Educational Pamphlet No. 1
Instructions regarding the attached "Message for Warriors in the South Seas"

To all units and militarized civilian personnel under my command:

This pamphlet, together with the previously distributed "Collection of Imperial Rescripts," to which are annexed: "Field Service Instructions" and "Read This and the War is Won", is to be used as material for the practical strengthening of morale in the field.

15 November 1941
Tomitaro Horii
Commanding General,
South Seas Detachment

Instructions given to the officers, men, and civilian employees under His Majesty the Emperor and under my command, on the occasion of the formation of the South Seas Detachment and their departure for operations:

In obedience to the orders of His Imperial Majesty, I now take command of your honored unit as an independent force, and am about to undertake a vital duty. I cannot repress my deep emotion, and I feel keenly the gravity of my responsibility.

I am convinced that the world situation surrounding East Asia faces an unprecedented crisis, and the fate of the Empire hangs in the balance. I believe that all of you, habitually bearing in mind the Imperial Edicts, have obeyed the orders of your superiors and have striven with all your might; however, at this time when your unit has been newly organized and is about to take the field, you are to stress to yourselves these three great principles with fullest courage:–

The strict observance of military discipline; the strengthening of esprit de corps; and the determination to fight to the death for certain victory. Whether you be under the higher commands or under the command of subordinate officers, whether you be officers or militarized civilian personnel, true to the spirit of loyalty, you are to have faith in and assist the combined action of the land and sea forces working together as one body; thus you shall do your utmost to utilize the results of your training and to display the combined fighting strength of the detachment.

You will take care of yourselves, bear in mind my wishes, and upon the opening of hostilities determine to exalt still more the true worth of the Detachment, swiftly bringing the Holy War to a successful termination, and thereby carrying out the Sacred Imperial Desire. ³⁶

The professional notebook of Ensign Toshio Nakamura, contains the following passage:

Address by our Captain upon the occasion of my boarding ship. Delivered by Capt. Yuji Takahashi (of the heavy cruiser Kako) 16 November 1941:

For three years you have studied your duties diligently. And now I believe that as you stand here, at the battlefront, your emotions have been heightened as you sense impending action.

When you reflect upon it, this is no training squadron; you have been assigned directly to the front.

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PLATE NO. 3
Resting Comrades

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Officers in charge of your guidance and their assistants have been selected; but the fact of the matter is that each and every one of them has his battle station and shall not be able to devote has wholehearted attention to your instruction. You appreciate, I am sure, the present situation and will not depend on others too heavily. You must undertake your duties assertively, with a healthy spirit of initiative. Moreover, at this time, special emphasis should be given to the caution, 'Always be at your station!'  It is extremely important that line officers always be on deck, so that they are able to master anything that comes along. In short, the present situation is certainly nearing its climax; indeed, it is in its most pregnant stage. I earnestly desire from you an uncommon amount of determination and effort.³⁷

Diary belonging to Superior Private Yamashita of 3d Battalion, 41st Infantry Regiment, contains the following entry:

18 November 1941–About 1530 hours left Shanghai, which has so many memories for me, and boarded Ryujo Maru at 1730 hours.... with Kiating as the objective, the brigade has been deployed for maneuvers in order to exploit all the more its success as a mechanized force. We are keenly feeling the pressure of the situation and orders have eventually come. The time has finally come for us to display activity. Are we going to be at war with the three powers A, B, and D?(Letters are written in English in the original). With a feeling of serious tension, 1 am aware that the most gratifying event since the beginning of Japanese history is the fact that we have now set out for the field.

21 November-Anchored in sight of Takao.³⁸

Partial translation of a file dated July–December 1941, entitled "No. 3 Situation of Both Sides Prior to the Outbreak of War," (issuing authority unknown), is set forth below. The section quoted is not dated, but it is apparent from internal evidence that it antedates 23 November 1941. The Tanaka Detachment landed in the vicinity of Aparri on 10 December 1941.

IV.  The Tanaka Detachment will start embarking at Takao between 23 and 25 November.  The plan of embarkation is as shown on the attached sheet. As from 0000 on 26 November, the Detachment will come under the direct control of Lt. Gen. Masaharu Homma, Commanding General, Fourteenth Army.  The troops newly attached to the force will come under the command of Tanaka Detachment as of 0001 hours on 26 November. . . .

Preparations having been finally completed, the convoy carrying Tanaka Detachment sailed at 1700  hours on the 7th from Mako Anchorage in the Pescadores under the direct guidance of escorts. Sailing through the Straits of Formosa in a rough sea, the officers and men were in high spirits.  No enemy airplanes or submarines were encountered.

During the evening a squall came up but the convoy sailed on. All were ready and anxious to meet the enemy.³⁹

Address No. 29 by the Commanding Officer of the light cruiser Katori, dated 26 November 1941 (Wednesday) at sea, and bound with a number of news reports and official communiques summarized by 00/61 Naval Intelligence Section, is set forth below. Part of the page was burned. A complete translation of the remainder is given

Thirty-seven years ago, when war between Russia and Japan became inevitable, the Emperor Meiji approached the Russian Government asking them to reconsider the declaration of war, to do everything possible to avoid the consequent calamity. We were extremely grateful for his benevolence.

Recently when Ambassador Kurusu was ordered to the United States–(I do not know whether he was sent for the same purpose as in the above incident before the Russo-Japanese War or not)–but at least

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I believe that he carried with him the Emperor's sincere hope that the evil of this war would be prevented. It is clearly known that this procedure is the tradition of our Empire.

In spite of the Emperor's benevolence, however, the American statesmen are arrogant and think that they are the greatest people in the world, and nothing can shake their belief. I suppose, therefore, in spite of the attempt of Ambassadors Nomura and Kurusu to prevent war, there is no hope of a peaceful settlement.

Ultimately, there is no other way to determine the outcome than by using our own force. At this particular time, we of the Katori, attached to Sixth Fleet, are about to take our place in the disposition of the fleet. Not only the submarine force, but also the Air force and surface units are mobilizing. It will not be long before operations begin.

I would like you to understand that when we put to sea the day before yesterday, it was not for an ordinary voyage, but for something entirely different. At this time, I would like you to bear in mind that we have an opportunity which comes but once in a lifetime.... ⁴⁰

Diary, presumably belonging to a member of 144th Infantry Regiment, contains the following entries:

17 November 1941-Today we held a review and ceremony for leaving for the field, participated in by all personnel of the unit....

21 November-Advance party left in the morning. Unit commander in charge of military flags left about 1300.

23 November-It rained during the morning and we departed in the rain. We left from Asakura Station at 1950, arrived at Sakaide about 0500....

24 November-Departed Sakaide. Matsue Maru left harbor at 1810.

25 November-We left the Inland Sea and headed southeast....

26 November-Our battle zone will be Guam Island. . . In the morning I went on deck and saw transports to the left, right, and rear. On antiaircraft observation duty.

28 November-Arrived at Haha-Jima about 1650. . . .

1 December-Held maneuvers during morning. Went on antiaircraft observation duty.  About 1500 ship (TN: or "ships") got under way.  Roused at 2200 for landing operations.  Roused again at 0100. About 0700 we returned to Haha-Jima Harbor. . . .

4 December-Gave Banzai facing toward Asamiyazo and left the harbor of Haha-Jima. At 0930 we proceeded southeast to "X". We received an order announcing the declaration of war.  We expected to land at "X " on the 10th.... ⁴¹

Diary of Seaman 2nd Class Tsuneya Kamimura contains the following entries:

22 November 1941-Went to Yokohama in the afternoon. Was invited aboard the Arima Maru for supper.

24 November-Sailed at 1400 hours. It is said that we are taking a direct route southward to Truk. Outside the harbor we sighted the Hikawa Maru.

Particularly on this voyage an air of seriousness prevails which has been lacking on most occasions. Received 10 Yen through telegraphic remittance. I presume that we will not be receiving any pay for a substantial period.

2 December-Left Truk at 0900 hours for Kwaja­lein. We cruised, sharply on the lookout for mines. Today is the fifth day of preparations, and dispositions have been completed. It is rumored that on the sixth day the Navy is to advance on a simultaneous general attack. Can it be a fact? Though I try to consider it calmly, my eyes and body reveal a state of excitement.

7 December-In the morning, after inspection of our division was concluded, the ship's captain gave us an address and read the Imperial message. We were instructed that action would commence at 0100 hours on the morning of the 8th.  I was very excited on hearing that Japan would declare war on the United States, Great Britain, and the Netherlands East Indies. Comfort packets were distributed among us. Was

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mightily glad to receive them. At 1900 hours we separated from the special service ship. After anchoring I drank beer and got drunk.⁴²

Personal history register of 1st Class Pvt. Tadatoshi Yamakawa of the 41st Infantry Regiment contains the entry quoted below. The original attack on Malaya was mounted from Samah:

28 November 1941-During assembly off Samah Harbor on Hainan, was admitted to a hospital ship from Kyushu Maru.

1 January 1942-Overtook his own unit at Kampar, Perak.⁴³

Diary, owner and unit unknown, but presumably a member of the South Seas Detachment, contains the following entries:

18 November 1941-From 1000 hours infantry group held war exercises under General Horii.

24 November-Left Marugame at 0630 hours. Boarded Matsue Maru at 1530 hours. Sailed at 1800 hours.

28 November-1650 hours stopped over at Haha­Jima, Ogasawara Archipelago.

29 November-Went ashore for communication. America has disguised herself till now. We are going to meet the enemy at Guam Island with ever-increasing spirit.

3 December-Landed Haha-Jima at 0230 hours to wash clothes. It seems that the Japanese-American talks will finally break down.

4 December-Worshipped the Imperial Palace at 0830. Gave 3 Banzais!  There was a speech. Japan-America, War!  It looks as though the hardships we have borne until now will be rewarded! We have received life for Showa's reign. Men have no greater love than this. Convoy to sail!  0900! Now, prosper, fatherland!"

4 December-South Haha-Jima at 1422 hours. The Empire has decided to go to war against America, Britain, and Holland. The Southern District Army will quickly capture important regions in the Philippines, British Malaya, and the Dutch Indies after beginning attack on 8 December.

'For this purpose the first Japanese air attack will be carried out.

'The South Seas Detachment will cooperate with Fourth Fleet to capture Guam. If there is no separate order, the landing will take place on 10 December.

'Horii Operation Order A, No. 17. Each unit will act according to Order A, No. 7, which has already been issued.'

8 December, 1100, war declared! ⁴⁴

Diary, owner and unit unknown, but presumably a member of the South Seas Detachment, contains the entries set forth below. The entry of 29 November 1941 anticipates a Japanese landing north of Talofofo Bay on Guam.

22 November 1941-0327 hours. Reached Sakaide. 1000 hours. Inspection tour of the Cheribon Maru.

23 November-1700 hours. Left Sakaide.

27 November-Sighted Bonin Islands.  0800 hours, reached Haha-Jima.

28 November-0900 hours. Went to Yokohama Maru for liaison.

29 November-Training for boarding motor barges during the morning. It has been decided that battalion will land on the north side of Taro Bay (presumably Talofofo Bay on Guam).

2 December-Anchorage point penetration training from 2000 hours.

3 December-Battalion officers to meet on Yokohama Maru from 0900 hours. Training in smoke flares and gas. Conference of company commanders, decided to land at Iriya Bay. Two first-class cruisers came to the anchorage point to escort us and we

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feel very safe.

4 December-The convoy left at 0900 hours.

6 December-Heard the Japanese news broadcast in the salon. Our mission is to attack the United States.⁴⁵

Diary belonging to Ifuji, a member of Palau No. 3 Defense Unit, contains the following entries:

29 November-War? All leave was cancelled and I heard that a huge Army unit is out here somewhere. (Written at Palau)

5 December-We received a written order from Commanding Officer of No. 3 Base to take up No. 2 Guard Dispositions from today; it is really going to be a serious affair.

6 December-It is said that American airplanes are reconnoitering our positions.

8 December-Declared war on America and Great Britain.⁴⁶

December 1941

Diary, owner and unit unknown, contains the following entries:

24 November 1941-Embarked on Daifuku Maru (3,523 tons) of N.Y.K. Line at Sakaide.

26 November-Destroyer Uzuki is escorting our convoy.

2 December-Loaded horses at Haha-Jima.

4 December-Order of Tomitaro Horii, South Seas Detachment Commander

On 2 December Imperial Japan decided on war with Great Britain, the United States of America, and Holland. Imperial Japan will, on 8 December, carry out its first air attack against the United States. This detachment will, if there is no special order, land on Guam.⁴⁷

Diary of Haruichi Nishimura, member of 1st Special Naval Landing Party, Yoshimoto Unit, contains the following entries:

7 November-Conscripted.

30 November-Boarded Kirishima Maru at Ujina. Escorted by Destroyers No. 36 and 37. Headed for Palau.

2 December-Heard over radio that American fleet (5 ships) had left harbor. Heard that we are to land on the Philippine Islands after resting at Palau.

5 December-Arrived Palau.

6 December-Enemy submarine sighted 5000 meters away.

7 December-Relations between United States and Japan are getting worse.

8 December-War was declared at 0800. Katsuta Maru sunk.⁴⁸

File of reports, entitled "Thailand Operations," belonging to the 77th Air Regiment, contains the following passage:

4-7 December 1941-Protection of Twenty-fifth Army transport convoy and preparation for occupation of Thailand.⁴⁹

Diary belonging to Shigeo Morikami, of Horii Force (South Seas Detachment), Takmori Unit, contains the following entries:

22 November 1941-Our departure for Sakaide leaving familiar Zentsuji behind. About 1930 hours left Sakaide Harbor behind, bound in 00 direction.

23 November-About 0500 hours our ship stopped. A mountain can be seen to the east, and a factory zone below it. My friends were saying that it was Senshuji.

27 November 1941-We also put in at Chichi-Jima at 0100 hours. We again departed for Haha-Jima at 1100 hours.

28 November-Landed the horses at Oki Village Grammar School on Haha-Jima.

3 December-Sailing preparations.

4 December-Will depart for Guam Island, which is called Omiyajima.

5 December-Will depart at 1000 hours. We are cruising safely.

6 December-Cruising safely. We will disembark

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in three days.

8 December 1941-Imperial General Headquarters. War was declared against England and the United States at 1230 hours. In the afternoon, I heard from Captain Takamori that the Hawaiian Islands are being bombed by our Air force. The Philippines and Hong Kong are also being bombed. At 0800 hours of the 8th, our Takamori Unit worshipped the Palace.  We will finally begin landing from 1200 hours of the 9th. On the morning of the 8th, some islands could be faintly seen for the first time.⁵⁰

Diary belonging to Yaichi Takahashi, of South Seas Detachment, Antiaircraft Unit, Takahashi Platoon, contains the following entries:

14 November 1941^-We finally received orders to go to the front. On 28 July we had separated from the friendly 73d Force in Korea and were reorganized as the 47th Antiaircraft Battalion. On 14 November at 0900, we carried out the last ceremony of farewell on the parade ground. When we were leaving for the front, Commander Fuchiyama gave instructions and read a written oath addressed to the Imperial Palace. I have no reluctance in giving my life and being killed in action. We went up to the Goku Shrine to pray for our ultimate victory.  We received sacred Sake from the god. Then we shouted "Banzai " three times and dismissed.

At 1900, we entrained.  We were on a freight car.  About 50 troops. All were waiting the time for leaving the friendly Kainei. . . .

17 November-At 0600, we eventually arrived at Pusan Station.  We stayed in Pusan City today.

18 November-Today the Iso Unit is leaving. At 1300, the loading was finished.  It was about two years since we were on a ship.  The inside of the ship was the same as when we came on her.  After a time I noticed that the ship was sailing.

19 November-This is Japan.  It was two years since I had seen Japan.  Ujina-the ISO Unit was divided into two groups here, then we were all embarked on the big ships.  I was in the Takahashi Platoon. The ship was the Matsue Maru.

On the 23rd at 0600, we arrived at our destination, Sakaide. At 1730, we finally left.  We did not know where we were going. On the 28th at 1630 hours, we caught sight of a big island northeast of the ship. Several ships which had come before us were at this island, Haha-Jima. It was four days since we left Sakaide. . . .

4 December-At 0930 hours, we eventually left the island. We immediately began to prepare for combat. Approaching enemy position.  We were on board 18 days, and every day was the same routine. On 11 December at 0100 hours, we came, at last, face to face with enemy positions.  We have a mission on Guam Island.⁵¹

Diary and notebook belonging to Yutaka Morita, of 144th Infantry Regiment, contains the following entries:

22 November 1941- 0140 hours. Arrived Sakaide Station in Kagawa Prefecture. Boarded the transport Moji Maru with 9th Company, one company of mountain artillery, 3 guns, 50 horses, cavalry, and part of an engineer unit.

1 December-Afternoon. Prepared for landing. Held landing practice. Warships and transports started out of Chichi-Jima at 1800 hours preparatory to departure.

2 December-0030 hours. Waited two hours with landing equipment but the motor boats were not ready and the landing was cancelled. The ships and transports returned to Chichi-Jima at 0600 hours, 1330 hours. Four warships, eight airplanes. Loaded some more horses on the ship again.

4 December-0930 hours. Warships and transports which were in readiness at Haha-Jima harbor sailed for their destination.

5 December-Convoy sailed south.

10 December-Landed Guam Island at 0400 hours.⁵²

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Diary belonging to Leading Pvt. Sagaei Matsuura, of the 144th Infantry Regiment, contains the following entries:

29 September 1941-Received induction orders.

5 October-Entered service.

8 October-Completed mobilization.

22 November-Embarked. Sailed in the evening. Arrived off Osaka in the morning. We did not sail during the day. Set sail at night.  Headed due south. We sailed southward till the morning of 27th. When I went up on deck in the morning, I saw a little island. It was one of the Bonin Islands.

27 November-Reached Chichi-Jima. Departed at 0900 hours the same day. Reached Haha-Jima before noon and anchored.  There are not many people living on this island. Ships come here one after another. The bay is filled with large ships.  It seems as though there are about seven or eight men-of-war here too. At first there were names on the warships; Uzuki, Yuzuki, and Kikuzuki etc., but the names were taken off.  This transport ship had MI written on the smoke stack but it also has been removed. Horses were unloaded on Haha-Jima. Horses and dogs romped around the hills. Those who had previously been here say that the women are not beautiful, but they speak the Tokyo dialect. We fished to pass the time till 4 December. In the meantime horses were loaded. I suppose we are again headed for hot places. We had mosquito nets and lunch boxes made for us.

4 December-Today we are really going to set out for our destination. We sailed around 10 o'clock. We started in the morning with a warship as escort. It was the Kurogame.  They were practically all carrying airplanes. As soon as we entered this harbor, two airplanes were started as if they had rehearsed going out on reconnaissance. There were many escort ships. As long as the Navy is present, there is nothing to be afraid of.

6 December-Tomorrow, we are told, Guam Island will be attacked and occupied. During the voyage all necessary preparation of arms, such as 150 rounds of ammunition, were in readiness.  With these we can kill. It is heavy, but I feel like taking more.

10 December-At 0200, we will bid farewell to this boat. We got on this boat on the 21st and started to sail on the morning of the 10th.  We lived on it for 20 days. At night we made various preparations for tomorrow's landing. I packed food for 3 meals in my haversack along with 150 rounds of ammunition. It is supposed to be packed as light as possible, but it is very heavy. We landed on one portion of the island which was barely visible in the dark. We anticipated enemy fire but did not encounter any. We landed successfully without incident.⁵³

Diary belonging to Gumpei Imoto, of French Indo-China Expeditionary Force, 106th Land Duty Company, contains the following entries:

1 November 1941-Reached Saigon at 0600 hours.

27 November-Left Saigon at about 1400 hours.

28 November-En route.

29 November-En route.

30 November-En route Taikai Maru.

1 December-Safely arrived in the morning at Hainan Island.

2 December-Still anchored at Hainan.

3 December-Remained aboard Taikai Maru until 1600 hours and transhipped to Kashii Maru. Stayed aboard that night.

4 December-Departed at 0600 hours for our destination.

7 December-Reached Singora safely at 2400 hours.

8 December-At 0300 hours, made preparations for opposed landing. Around 0600 hours an unopposed landing was made. Took the enemy completely by surprise.⁵⁴

Diary belonging to Chitoshi Sato, of South Seas Detachment, contains the following entries:

14 November 1941-Departed for Pusan.

15 November-Travelling south by train.

16 November-Still on train.

17 November-Approached Keijo.

19 November-Loaded guns on ship and sailed from Pusan harbor.

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20 November-Entered Moji harbor at 0700 hours, loaded coal at Ujina harbor, was separated from battery commander and 2d Lieutenant Takahashi. Loaded guns on Matsue.

22 November-Left Ujina harbor for Sakaide. Went through Inland Sea.

24 November-Left Sakaide in the evening.

27 November-Escorted by warship Uzuki.

28 November-Arrived at Ogasawara Islands.

29 November-Landed at Haha-Jima.

30 November-Picked bananas, coconuts, and papayas at Haha-Jima.

4 December-0900 hours left Ogasawara....

10 December-Infantry made opposed landing at Guam this morning at 0100 hours.⁵⁵

Diary belonging to Susumu Kawano, of 106th Land Duty Company, contains the following entries:

23 September-Drilled. Inspection for all mobilized personnel. From 0700 hours visitors were allowed in camp area.

6 October-1700 hours arrived Saigon.

23 November-Left on transport Tokokawa Maru.

25 November-Arrived Samah, Hainan Island. Transferred to Kashii Maru.

5 December- 30 transports headed towards the theater of operations with naval escort.

8 December-Made opposed landing at Singora, Thailand.⁵⁶

Diary, owner and unit unknown, contains the following entries:

24 November 1941-Arrived at Haikow, Hainan Island.

27 November-Left Haikow.

30 November-Arrived at Humen.

2 December-Left Humen.

4 December-Arrived Samah harbor.

5 December-Sailed from the harbor at 0400 hours for operations.

8 December-Arrived at Singora, Malay Peninsula at 0140 hours.⁵⁷

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