The Government (Cabinet) was dominated by the military in the persons of the War and Navy Ministers, both invariably from the active lists of the Army and Navy. Cabinets fell and were formed at the whim of the military; the resignation of either minister terminated a cabinet and failure of either branch of the services to nominate a minister prevented the formation of a new one.
An equally important point to be borne in mind is that the two factions of the all-powerful military, the Army and the Navy, exercised their authority only through mutual agreements. Unless an agreement was reached between these two factions, nothing could be accomplished.
The Imperial Headquarters, which was created only in time of war for the purpose of assuming supreme military command, was formed in November 1937. Its nucleus was the two general staffs, and it was headed by the Chiefs of Staff of the Army and Navy. As Commander in Chief of the Army and Navy, the Emperor was the titular head of this body, though the practical extent of his authority is not clear. What was discussed and agreed upon within this Headquarters was known only to the members. This headquarters was primarily concerned with operational plans, though being the supreme military command body it had great influence on national war policies. Within this headquarters Chief of the Army General Staff determined all matters concerning Army operations, and similarly the Chief of the Naval General Staff determined all matters concerning naval operations. Should there develop a difference of opinion between the two Chiefs, and should agreement not be reached, stalemate and inaction resulted.
The Government (Cabinet) was composed of the Prime Minister, the War and Navy Ministers, the Foreign minister and various other ministers. This body was primarily concerned with the economic and political administration of the nation and with the provision of the material and man power for the conduct of the war.
The Supreme War Council was the chief advisory body in formulation of war policies and was composed of members of the Board of Field Marshals and Admirals, the War and Navy Ministers, the Chiefs of Staff of the Army and Navy, and other high officers (including former War and Navy Ministers) appointed by the Emperor. The Imperial Headquarters however had more of a voice in formulating national policies than this unwieldy council. As a result of reverses, the Supreme War Council was superseded in August 1944 by the Supreme Council for the Direction of War. Although the Supreme War Council continued to exist, it retained little power. This Supreme Council for the Direction of War was established primarily to facilitate formulation of fundamental policies for the conduct of the war, and to obtain a national unity in the prosecution of the war. It was not concerned with operational plans, and acted chiefly as a liaison organization between the Imperial Headquarters and the Cabinet. It was composed of six voting regular members: the Prime Minister, the War and Navy Ministers, the Chiefs of Staff of the Army and Navy and the Foreign Minister. In addition, the regular members could bring any other minister to a meeting although these latter had no vote. The Deputy Chiefs of Staff also attended but did not vote. On occasion, and by Imperial Order, the President of the Privy Council would attend. When matters of special importance were to be discussed, the Emperor was requested to attend the meetings. There were also occasions when informal meetings were called by the Emperor; this occurred twice in June 1945 when attempts were being made to terminate the war.
During the later stages of the war liaison conferences were held every Tuesday and Friday at the Imperial Palace, but were not attended by the Emperor. Conferees were the Chiefs of Staff, their Deputies, the Chiefs of the 1st Sections (Plans), the Chiefs of the Operations Sections, and other senior officers of the Army and Navy General Staffs. Towards the end of the tenure of office of the Koiso cabinet, these conferences were attended by the prime Minister and the War and Navy ministers. At these conferences operational plans of the Army and Navy, and joint operations were discussed. However, no decisions were made.
Within the Naval General Staff, naval planning was accomplished in the First Section of the First Department, which section was concerned with operational planning. Logistic Planning was done in the Second Department, Naval Intelligence was provided by the Third Department, Communication Planning was done in the Fourth Department, and radio Intelligence was provided by a special section. Naval operations plans originated either in the First Department of the Naval General Staff or in the Headquarters of the Combined Fleet. After discussion by the Chief of the Naval General Staff and the Commander in Chief of the Combined Fleet, the final plans were drawn up. As previously mentioned these operational plans were discussed at the liaison conferences between the Army and Navy. Important plans were discussed at the Imperial General Headquarters and the agreement of the Army General Staff was obtained before the plan was submitted to the Chief of the Naval General staff. If the plan involved participation of the Government in providing necessary material and personnel, steps were taken to obtain the Navy Minister's agreement.
If the contemplated operations were of great importance, the directives were issued in the following manner: For those operations which extended beyond the authority delegated by Imperial Directive to the Chief of the Naval General Staff, the plan was submitted through the Imperial Headquarters to the Emperor for approval, after which it was issued as an order of the Naval Staff, Imperial Headquarters. Directives for plans of lesser importance which did not exceed that authority were issued in the name of the Chief of the Naval General Staff, but by direction of the Naval Staff, Imperial Headquarters.
II. Consolidation and strengthening of the defensive perimeter.
III. The interception and destruction of any attacking strength which might threaten the defensive perimeter or the vital areas within the perimeter. Concurrently with intercept operations the activation of plans to destroy the United States will to fight.
By the successful accomplishment of the three phases of this plan the Japanese hoped to attain the goal of this war, making Japan self-sufficient.
Upon the successful completion of the first phase, and influenced by the unexpected ease with which their initial operations were carried out, the activation of the second phase was delayed and plans were formulated for further expansion.
These expansion plans were for the purpose of extending Japanese control of the Pacific and provided for the following:
Upon completion of these expansion operations, the consolidation of position was to be completed as follows:
Every effort was to be made and every opportunity seized to reduce Allied air and surface strength by raiding tactics.
The unexpected success of the operations in the first phase, and the ease with which these oprations were carried out, caused the Japanese to underestimate the existing United States strength and to embark on a further expansion. This policy of further expansion was hotly debated; however the faction in favor of pushing the initial advantages won out. The air raid on Tokyo on 18 April 1942 had some influence on this decision in that it tended to confirm the need for additional bases to the east. As they stated, the reserve strength which should have been used in consolidating the positions seized in the initial phase was dissipated in the unsuccessful attempts at further expansion. In view of the limitations of Japnese miltiary strength, shipping, and the national economy, this attempt to expand an already too big strategic sphere brought about unsolvable problems. At the time when the defenses of those areas which had to be held at any cost were left wanting, operations for the capture of port Moresby, Midway, and the Aleutinas were undertaken, thereby further dissipating the nation's strength. Thus it was conceded that the expansion program which was intended to strengthen the Japanese defense position actually weakened it. All the
Japanese interrogated on this subject considered that this expansion was a fundamental error in the conduct of the war.
The losses sustained in these unsuccessful attempts at expansion beyond the original outlined perimeter proved to be the greatest handicap in carrying out subsequent naval operations. It was stated that the loss of a major portion of their carriers in these operations was a serious blow to their naval air strength and, after still further air losses during the Solomons Campaign, the Japanese Naval Air Force never fully recovered.
When the Japanese were forced to return to their original plan of consolidation, it was with greatly reduced strength. Although priority was given to the construction of carriers and the strengthening of their air forces, they stated that they were unable to match the speed of the United States counteroffensives, and that they were continually behind schedule in the building up of defenses and the training of their air forces.
After the Battle of Midway, in which the Japanese carrier forces sustained such heavy losses, most of the strength which they could muster had to be used in the attempts to counter United States offensive operations. Thus after the early raids, Japanese carrier forces were unable to continue these operations against Allied bases. With their carrier forces reduced to relative impotence, the Japanese attempted with small success to conduct raids using land-based air forces. United States opposition increased at every point while the training and quality of Japanese air forces declined steadily. Toward the end of the war, the chief Japanese hope seemed to lie in raids against United States advanced bases by special attack (Kamikaze) forces. Such raids on anchorages were carried out by submarine-borne "human torpedoes" in early 1945, and by a special attack force of airplanes on Ulithi in March 1945. Again they were not considered highly successful, although abortive attempts were made to repeat the latter.
The Japanese in analyzing these raiding tactics, felt that they started too late to originate and to prepare and train for that type of operation -- the use of suicide tactics of all types. They continue to feel that, had adequate advance preparations been made and the inherent spirit of the special suicide attack been fully utilized, these tactics perhaps would have reversed the tide of battle.
As regards surface raiders, very little preparation and training was carried out before the war and the results obtained by these forces were very slight.
As a result of heavy losses suffered in combat prior to the threat of major air attacks on her homeland, a large part of her effective fighter strength had been destroyed. Lack of aviation gasoline and the need for conserving their remaining strength for the defense against invasion, resulted in orders to disperse or conserve the remaining fighter strength.
The dispersal and moving underground of essential industries, as well as the evacuation of the metropolitan areas, were not effected until it was too late.
Operational plans for defending the vital areas and the defensive perimeter were prepared. The objective of these plans was to defend these areas, to destroy United States forces which attempted to attack the defense perimeter, to cut United States lines of communication, and to establish a strategically strong position. In support of these plans every effort was to be made to build up naval air forces, both carrier and land-based.
In order to achieve this purpose, the following operational tasks were to be performed:
In accordance with the foregoing, and in cooperation with the Army, a speedy strengthening of defenses was attempted. However the carrying out of this task was beyond Japanese capabilities.
The "Z" Operation Plan (formulated about May 1943)
The operational policy of this plan was:
The tasks to be performed were as follows:
As a result of the Munda and Kolombangara landings and the landings at Lae and Salamaua, it became apparent that Rabaul could no longer be considered an effective position. Therefore, at the end of September 1943, the defense line was withdrawn and the vital area was reduced to that within the line Kuriles-Marianas-Carolines, and the Sumatra-Java-Timor line. Efforts were then concentrated on the strengthening of these areas and on sending reinforcements. But due to the lack of shipping the desired results were not achieved.
The United States occupation of the Gilberts and Marshalls was resisted with only inadequate land-based air and local garrisons. As these areas had been removed from the vital area in September 1943, the Combined Fleet was not committed. A further reason for not committing the fleet was that, as a result heavy losses sustained by the carrier air groups at Midway and in the Solomons, the carrier divisions were not ready for operations. The "Z" plan, in modified form, remained in effect until May 1944, when it was cancelled and superseded by the "A" plans.
The "Y" Operations Plan (formulated about May 1943)
The operational policy and tasks for this plan were similar to those for the contemporary "Z" Plan, except for the area of operations. The front line of defense prescribed in this plan was that joining the Andamans, Nicobar, Sumatra, Java, and Timor. In case this defense line alone was threatened, the main strength of the Combined Fleet was to be moved to the Philippines or to Singapore. In case this defense line was threatened and the "Z" Plan also activated, then only a portion of the carrier force was to be utilized, together with local forces available.
The position of forces prescribed by this plan was:
The "A" Operations Plan (formulated May 1944)
At the end of February 1944, the Gilberts and Marshalls had been occupied and Truk and the Bismarcks neutralized and bypassed. The outer defense was then further withdrawn to the Marianas, Palau, and the Sumatra-Java-Timor-Western New Guinea line. The "A" plan was drawn up for a decisive action in defense of this line. Force necessary for this operation were expected to be ready the latter part of May 1944.
The objective of this plan was to concentrate all available forces for a decisive action against United States attack forces.
The tasks to be performed were as follows:
The disposition of forces prescribed by this plan was:
The preparations for the decisive action under this plan were never completed as planned and the training of the air force, particularly the carrier air groups, was behind schedule. The Japanese considered that the carrier air groups would be ready in August. In view of the United States carrier strike on Palau in the latter part of March 1944, and the occupation of Hollandia in April, the Japanese estimated that the next attack would be against Palau, which also was a scene of action favorable to their plan.
However, when United States forces appeared off Saipan in June and initiated their assault the "A" plan was activated even though complete preparations had not been realized. In the ensuing battle of the Philippine Sea, the major portion of their carriers and practically all of the carrier air groups were lost. In addition the shore-based First Air Fleet suffered severe losses. These losses to the Japanese Naval Air Force vitally affected all subsequent operations, and the prospect of success in future operations at sea became very dim.
The "Sho" Operations Plan (formulated in July 1944)
After the fall of the Marianas, and as a result of the heavy losses sustained in that campaign, the Japanese considered that any attempt to recapture these islands was out of the question. The United States had obtained control of the Central Pacific areas. This again forced the Japanese to further withdraw their defense line to one running from the Home Islands through the Nansei Shoto, Formosa, Philippines, and Timor-Java-Sumatra. The "Sho" plan was drawn up for a decisive action in defense of this line, with the probability that it would take place in the vicinity of the Home Islands, Nansei Shoto, Formosa or Philippines. The Nanpo Shoto was also considered as a possible scene of action. The next attack was expected some time after August 1944.
The operational policy of this plan was:
In accordance with the estimate of the probable areas of action, and in order to facilitate preparations and to establish command relationships the following four plans were drawn up:
Sho Number 1--Philippine Area.
Sho Number 2--Formosa-Nansei Shoto-Southern Kyushu Areas.
Sho Number 3--Kyushu-Shikoku-Honshu Areas.
Sho Number 4--Hokkaido Area.
As the Sho Number and 1 and Number 2 were considered most likely to be activated, priority was given to strengthening the defenses in these areas. After a brisk discussion between the Army and Navy, it was agreed that an all-out land defense would be made only if the action were to occur in the Northern Philippines. If the action were to occur in the central or southern part, only air and surface forces would seek decisive action.
The tasks to be performed were:
The initial disposition of forces prescribed by this plan:
Palau and Morotai were attacked in September, the Japanese estimated that the next move would be against the Philippines so no changes were made in the "Sho" plan. When in October the attacks did occur on the Central Philippines, the "Sho" plan was activated and, in accordance therewith, the Fleet was committed and reinforcements were dispatched to Leyte.
The Battle for Leyte Gulf was a complete defeat for the Japanese Fleet. In it the major portion of the remaining Japanese naval surface strength was destroyed. In addition the Army and Navy air forces in the Philippines suffered severe losses. This campaign also saw the initiation of special attack (Kamikaze) tactics.
The "Ten" Operation Plan (formulated in early March 1945)
With the occupation of the Central Philippines and the establishment of United States air bases in this area, the final severance of lines of communication between Japan and her vital resources was accomplished. The Japanese estimated that United States strategic plans were aimed at positions surrounding the China Sea, with the most probable objective being in the Nansei Shoto. With operations continuing throughout the Philippines, the Japanese did not expect that Formosa would be attacked. The "Ten" plan was formulated for the final defense of an inner line established through the Home Islands, the Nansei Shoto, Formosa and the South coast of China. With the Japanese fleet almost completely destroyed and the air force reduced to the employment of suicide tactics, a "decisive action" was no longer possible and only a "last ditch" defense was contemplated.
The operational policy for this plan was:
In order to facilitate defense preparations in the probable objective areas, and to establish command relationships, the following four plans were drawn up:
Ten Number 1--Nansei Shoto-Formosa area.
Ten Number 2--Formosa.
Ten Number 3--Formosa-East and South coasts of China.
Ten Number 4--Hainan and areas to the westward.
The tasks to be performed were:
The disposition of forces prescribed by this plan was:
In accordance with plans Iwo Jima was defended only by limited operations of naval land-based air forces. However the United States amphibious assault on Okinawa was opposed by large-scale suicide attacks and a desperate suicide sortie by the battleship Yamato with an escort of light vessels. Heavy losses were suffered by the remnants of the Japanese Army and Navy Air Forces.
The "Ketsu" Operation Plan (formulated at the end of March, 1945)
With the fall of Iwo Jima and Okinawa, the last line of defense was broken; the air and sea blockade of the Home Islands was complete. The next projected advance of the United States forces was obviously the invasion of the Home Islands with the Southern Kyushu and the Kanto area the most probable objectives. The "Ketsu" plan was drawn up for the final defense of the Empire.
The operational policy for this plan was:
The tasks to be performed were:
The disposition of forces was:
Preparations for these operations were considerably disorganized by increasingly heavy United States raids by land-based and carrier-based planes. Attacks preliminary to the invasion were being systematically conducted against all of the Home Island by Allied carrier forces. These attacks included shore bombardment by heavy ships and shipping sweeps of coastal waters by light surface forces.
The Imperial Rescript of 14 August 1945 terminated hostilities, and on 2 September 1945 the surrender terms were executed.