As the year 1945 began, the Japanese nation faced disaster.1 The great decisive battle in the Philippines had been lost, and the enemy was moving on to invade Luzon, wresting from the Japanese their last operational base in the Philippines and extending the Allied air perimeter far out over Formosa, the China coast and southern Japan. Behind General MacArthur's forces hundreds of thousands of trained Army, Navy, and Air Force personnel were isolated, unable to contribute directly to the prosecution of the war. Ahead of the enemy, the road to the Japanese Homeland lay wide open.2
The war potential of the nation was at a record low. The backbone of both the fleet and the air forces had been broken in the Philippines, while the Army's ability to concentrate for a final effort was hampered by its commitments to many scattered and now isolated theaters. More serious than even the long chain of tactical defeats which had all but destroyed Japan's armed forces, however, was the rapid disintegration of the national war economy at its base.
Largely as a result of submarine interdiction of the South China Sea, the nation had already been deprived of essential strategic raw materials. Only in the early part of the war had Japanese shipbuilding facilities been able to keep up with sinkings by Allied submarines and planes. By January 1945, 69% of Japan's merchant fleet, including 59% of her vital oil tankers, had been sent to the bottom. Total gross cargo loadings in the quarter ending in December 1944 were a mere 33 of the wartime peak.3
As a result of the crisis in shipping, the flow of coal, iron ore, non-ferrous ores and concentrates, salt, and chemicals from the Asiatic continent had been materially reduced, while the supply of oil, rubber, nickel, chromium, and
aluminous concentrates from the southern area had slowed to a mere trickle.4 General MacArthur's seizure of Luzon and operations of the American carrier task force in the South China Sea gave notice that even this slender lifeline was about to be decisively severed.5
The collapse of Japan's overseas supply of raw materials was immediately reflected in the production figures of her basic industries. By early 1945, the iron and steel industry was operating at only about 49% of its wartime peak production, the three most important non-ferrous metals, copper, aluminum, and magnesium, were off 49% from their peak, and a similar situation obtained in the output of ferro-alloys. The chemical industry was producing at 62 of the first quarter of 1944, while the total production and import of crude and refined petroleum was down to a disastrous 26% in the quarter ending in December 1944. From the long-range strategic viewpoint, the situation had become hopeless.6
For their part, the Allies seemed to be in an extremely favorable position. In the European theater, the failure of the Germans' great Ardennes offensive presaged the defeat of Japan's distant ally, and it was a certainty that termination of hostilities in that area would be followed by the redeployment of overwhelming land, sea, and air power against Japan. Intelligence reports disclosed that the United States was rushing production of all types of amphibious
craft, heavy bombers, tanks, artillery, new rocket weapons, and fleet carriers.7 In the Philippines and the Marianas the enemy had excellent staging bases from which to launch the next effort.
In this disheartening atmosphere, Imperial General Headquarters undertook to determine the probable course of future Allied action. In general, it seemed clear that the United States would desire to bring the war to an early conclusion, and that the ultimate goal of enemy strategic policy would be the annihilation of the Japanese Army in the Homeland and the occupation of Japan. To prepare for the ultimate invasion, the High Command felt that the enemy would take the following course of action.8
A direct attack on Japan Proper without these preliminary steps was regarded as a remote possibility. Within the framework of the most probable Allied strategic plan, it was believed that Iwo Jima in the Bonin Islands would be the next invasion target, with Okinawa in the Ryukyus following soon thereafter.
An inventory of the forces available to meet the expected onslaught gave the High Command no cause for optimism. The basic compo sition and deployment of forces adopted for the Sho-Go operations still survived in principle, weakened and modified however by the heavy commitment to the Sho No. 1 front in the Philippines. Under Imperial General Head quarters there were two major commands responsible for the defense of the Homeland. The General Defense Command, under General Prince Naruhiko Higashikuni, was re sponsible for the air and ground defense of Honshu, Shikoku, Kyushu, and the Izu Islands, and for a portion of the long-range air operations against enemy invasion convoys and bases. The Combined Fleet, under Admi-
PLATE NO. 141
ral Soemu Toyoda was responsible for all surface operations and the bulk of the long-range air operations over the approaches to the Homeland. (Plate No. 142)
Peripheral commands under Imperial General Headquarters included the Fifth Area Army under Lt. Gen. Kiichiro Higuchi, responsible for Hokkaido, the Kurile Islands, and Karafuto;9 Lt. Gen. Tadamichi Kuribayashi's Ogasawara Group in the Bonin Islands; and the Tenth Area Army under General Rikichi Ando, responsible for Formosa and the Ryukyu Islands.
For the land and air defense of Japan Proper (excluding Hokkaido and certain naval stations), the Commander-in-Chief, General Defense Command, had at his disposal the Western District Army (Lt. Gen. Isamu Yokoyama), responsible for Kyushu and southwest ern Honshu, the Central District Army (Lt. Gen. Masakazu Kawabe) in central Honshu and Shikoku, the Eastern District Army (General Keisuke Fujie) in northeast Honshu and the Izu Islands, the Thirty-sixth Army (Lt. Gen. Toshimichi Uemura) as a mobile reserve in the Kanto-Shizuoka area, and the newly-activated Sixth Air Army.10
To execute the Combined Fleet mission, the Commander-in-Chief had available Vice Adm. Seiichi Ito's Second Fleet, now engaged in
repair and training activities in the Hiroshima-Kure area11 and the Sixth Fleet under Vice Adm. Shigeyoshi Miwa, comprising Japan's 52 remaining submarines. For long-range offensive air operations Admiral Toyoda had at his disposal the Third Air Fleet under Vice Adm. Kimpei Teraoka in the home islands, the First Air Fleet under Vice Adm. Takijiro Onishi in Formosa,12 and Rear Adm. Chikao Yamamoto's 11th Air Flotilla, an independent unit, on Kyushu. Of these, only the latter was at this time in a state of real combat readiness.
With the disintegration of the Japanese surface forces, the burden of intercepting invasion threats against the Homeland fell almost exclusively on the air establishment. The air situation, however, was extremely discouraging. Only about 550 aircraft were available for offensive purposes. Distribution of strength was as follows:13
The situation in regard to defensive air strength, vitally needed to guard the Homeland against large-scale enemy air raids from newly-won bases, was equally bad.14 Available
PLATE NO. 142
for this purpose was a total of about 770 air craft and 1200 antiaircraft guns for all of Japan Proper (excluding Hokkaido). Air defense operations were decentralized, each District Army having under its command an air division for interceptor operations and a number of antiaircraft units. Disposition of the air strength attached from Sixth Air Army was as follows:15
In addition, the 302d, 332d, and 352d Naval Air Groups were attached to the Eastern, Central, and Western District Armies respectively for interceptor operations. This added about 100 fighters to the air defense system. These Army and Navy forces were concentrated principally in the Tokyo-Yokohama, Osaka-Kobe, and Shimonoseki-Moji areas, and around vital naval installations such as Yokosuka, Kure, and Sasebo.
Primary emphasis in the Sho No. 3 plan, formulated in the summer of 1944, had been placed on sea and air operations.16 As a result, the build-up of ground combat forces in Japan Proper during late 1944 had been on a very modest scale. A total of only eight divisions was available for operations in Japan Proper (excluding Hokkaido).17 The command system and deployment were as follows:18
Under the Sho No. 3 plan the mission of these units had been mainly the construction of coastal defense works in southern Kyushu, the Kanto plain, the Toyohashi-Hamamatsu area in central Honshu, and the Hachinohe district at the extreme northeastern tip of Honshu.19 At the beginning of the year, construction of semi-permanent artillery positions was on schedule. Construction of infantry positions, on the other hand, was lagging seriously. Only in the Ariake Bay area of southern Kyushu were they more than 40% complete. In the Toyohashi and Hachinohe districts, completion had only reached about 10%, while in the Kanto area, construction had just been started.20
In contrast to the small beginnings that had been made on the defenses of Japan Proper, strong ground formations had been disposed on the Homeland defense perimeter. On Formosa and the Ryukyus was the Tenth Area Army with a powerful force of eight divisions, seven independent mixed brigades, and an air division.21 The Ogasawara Islands were garrisoned by the Ogasawara Group, a heterogeneous combat formation built around the 109th Division.22
By mid January 1945, the progress of events clearly indicated the need for a new and far-
reaching strategic plan to replace the now-defunct Sho-Go plan. In the pessimistic and confused official atmosphere of this period, further complicated by inter-service differences, it was difficult to formulate even the most general of policy directives.23 However, the need for action was imperative, and Imperial General Headquarters, on 19 January, submitted for Imperial sanction the draft of a general policy directive known as the "Outline of Army and Navy Operations." This directive, having been approved by the Emperor, was officially promulgated on 20 January and became the basis for all future Homeland defense planning.
Pursuant to this basic policy directive, the Army Section of Imperial General Headquarters assigned missions to its major subordinate commands as follows:25
On 30 January, the Navy Section of Imperial General Headquarters conducted a conference in Tokyo of the chiefs-of-staff of all fleets and naval districts. The "Outline of Army and Navy Operations" was presented to the conference and preliminary plans and general missions promulgated.
Immediately following the publication of the "Outline of Army and Navy Operation," joint conferences were held to iron out difficulties in the actual implementation of the plan. The first and most important problem was to formulate a sound and workable air policy. Efforts in that direction culminated on 6 February in the drafting of a Joint Army-Navy Air Agreement for the first half of 1945. This was to be subject to ratification by the two services
PLATE NO. 143
after study on the operational levels. In it essentials, the draft was as follows:28
On the same day that the draft of this joint agreement was issued, the Army Section of Imperial General Headquarters published an implementing directive entitled "Outline of Air Operations in the East China Sea Area." In addition to the provisions of the joint agreement on which it was based, this plan contained detailed directions for the preservation and replenishment of existing units, strengthening of bases, and the redeployment necessary to bring the required air power into the theater by 1 April. This plan, designated the Ten-Go Operation Plan, became the basis for all future Army air operations over the East China Sea Area.29
To prepare for the forthcoming operations,
the Navy, on 10 February reorganized its air units within Japan Proper. The Third Air Fleet, with headquarters in the Kanto district, was relieved of all further responsibility for the Kyushu-Ryukyus area and assigned exclusively to operations in central and eastern Honshu. The Fifth Air Fleet was activated on Kyushu, absorbing the 11th Air Flotilla and all former Third Air Fleet units in the area. It assumed responsibility for future naval air operations in the East China Sea area under the joint agreement.30
For further implementation of the "Outline of Army and Navy Operations," Imperial General Headquarters quickly realized that reorganization and redeployment of the ground establishment was also imperative. Of first priority was the reorganization of the major commands in Japan Proper. This was accomplished by a War Ministry order of 22 January and an Imperial General Headquarters order of 6 February, which transferred the operational missions of the old district armies to a number of new area Army headquarters.31 New district Army commands were established in each area Army zone to assume responsibility for logistics and administrative matters.32 The General Defense Command was now constituted as follows: (Plate No. 144)33
PLATE NO. 144
The reorganization of the high-level headquarters in Japan Proper was of course only a first step toward building up the ground combat forces. Although one division had been added to the Homeland forces on 22 January,34 there were still too few troops to garrison even the most critical points. Concurrently with the activation of the Homeland area armies, therefore, the Army High Command ordered the immediate organization of four independent mixed brigades as an emergency mobilization to fill the most critical gaps as rapidly as possible. These were as follows:35
Following this emergency measure, the Army undertook to establish a firm troop basis for the future Homeland defense armies. Discussions between the War Ministry and the High Command culminated on 26 February in the adoption of a plan calling for the mobilization of 42 divisions,18 independent mixed brigades,36 and six tank brigades, the bulk of this force to be added to the one armored and eight line combat divisions and seven independent mixed brigades at that time active in the General Defense Command. These units, together with the required logistic and administrative support elements, would contain a total of about 1,500,000 men. Mobilization of this enormous force was to be accomplished in three stages, the first from late February to early April, the second during April, and the last by the end of September. To provide the necessary high level headquarters, it was also planned to activate nine Army headquarters for tactical field command and two general Army headquarters to exercise command at Army group level. The activation schedule for units in the Homeland (less Hokkaido) was as follows:37
In addition, during the period of the second mobilization, three line combat infantry divisions and one armored division were to be moved from Manchuria to the Homeland. This redeployment, together with the planned mobilizations, brought the projected total of Homeland (less Hokkaido) defense ground forces to a basic combat strength of 26 line combat divisions, 22 coastal combat divisions, and 21 independent mixed brigades.39 Armored composition was fixed at two armored divisions and six tank brigades.
The problem of supplying weapons and equipment to the new units was a serious one. However, when the mobilization plan was drafted, the total amount of weapons in the hands of Army ordnance supply, together with those to be produced during February and March plus weapons slated for transfer from the continent, was fortunately sufficient to permit a large enough initial issue to enable the units to begin their training.40 Provided production could be held at present levels, it was felt that the ordnance industry could fill the remaining combat equipment requirements by September. On this basis, the War Ministry set the following ordnance production targets for the period April through September:41
The production schedule for sea special-attack weapons was simultaneously set as follows:42
Aircraft production presented a special problem due to the concentrated attention being given the industry by enemy air units. Based on the assumption that production could be increased slightly over the average output in December and January,43 the Supreme War Direction Council adopted a figure of 16,000 planes as the goal for the period April through September.44 Production during the quarter ending in March was to be allocated exclusively to the Ten-Go Air Operation.
Long-range preparations for the defense of the Homeland had barely gotten underway when enemy attacks on the defense perimeter began. On 19 February, a powerful U. S. amphibious task force launched an invasion of Iwo Jima, keystone of the Ogasawara Island sector of the perimeter.
At the same time, the enemy violently accelerated the aerial offensive against Japan Proper, striking heavily at industrial targets and airfields in Tokyo, Osaka-Kobe, and Nagoya. From a total of 598 sorties flown over Japan Proper in January, Allied air activity rocketed to 3,193 sorties in February.45
To slow up the mounting American air offensive against Japan, it was imperative that the enemy be denied forward bases on the Homeland defense perimeter. Iwo Jima consequently assumed an importance far out of proportion to its actual size and facilities, because from its airfields enemy fighter planes would be able to fly both escort and attack missions over almost all of Japan Proper south of Sendai. (Plate No. 146)
Despite the importance of Iwo Jima, the Japanese were unable at this time to make any large-scale air commitment to its defense. The Ogasawara Islands did not afford a good chain of mutually supporting bases, and they were too far from Japan Proper. In any case, the Japanese air establishment was still in too debilitated a state to seek a decisive battle in the area. The defense of Iwo Jima therefore fell exclusively to the ground forces. For over a month Lt. Gen. Tadamichi Kuribayashi's Ogasawara Group (109th Division) held out against immensely superior American forces, fighting a tenacious battle in the many excellent caves and field fortifications on the island. By 22 March, despite this heroic resistance, Iwo Jima fell completely into enemy hands.46
As the campaign on the Homeland defense perimeter began, the enemy unleashed a series
of air attacks on large urban areas in the Homeland which rocked the nation to its very foundations. Switching from high explosives to incendiaries, the B-29's began these operations on the night of 9-10 March with a heavy raid on Tokyo. The new tactics caught the Japanese completely off guard, and the re sults were indescribably horrifying. Well over 250,000 houses were destroyed, rendering more than a million persons homeless, and 83,793 were burned to death.47 Between 10 and 17 March, raids on the same pattern were flown against Osaka, Kobe, and Nagoya. B-29 raids from November through February had been little more than an annoyance to the Japanese, but with the beginning of the fire-bomb campaign, enemy strategic bombing loomed for the first time as a threat to the entire social and economic fabric of the nation.
With the invasion of Iwo Jima and the sudden acceleration of the aerial offensive against Japan, it was clear that a move into the East China Sea area could not be far distant. The Navy, which had originally entertained considerable reservations about an air operation in that area before May, suddenly took steps to meet the emergency.
First of all, the Army-Navy Air Agreement of 6 February, which until now had been considered a highly tentative document, was formally ratified by the Navy High Command on 1 March. At the same time, plans were made to strengthen naval air participation in the forthcoming campaign. The 11th, 12th, and 13th Combined Air Training Groups were converted into operational units. To take over the new groups, Tenth Air Fleet was activated on 1 March in the Kanto district, Vice Adm. Minoru Maeda assuming command. The Third Air Fleet, whose mission under the original plans had been to garrison eastern Honshu and provide a reinforcement pool for the East China Sea air battle, was now informed that, upon the activation of the operation, it would immediately displace to Kyushu in full strength. Both the Third and Tenth Air Fleets were ordered to begin intensive training in special-attack methods. This training was to be completed by the end of April, when Tenth Air Fleet was also to move to Kyushu bases. The planned strength of Navy air units in the East China Sea operation was now fixed as follows:48
On 20 March, the Navy High Command issued an over-all policy directive which clearly set forth the basic concept of the Navy's participation in the Homeland defense campaign. This document, entitled the "Imperial Navy Outline Plan of Immediate Operations," contained the following general provisions:49
PLATE NO. 145
Meanwhile, the preliminaries of the East China Sea air battle were already underway, giving the Japanese no time to complete their long-range preparations. Early on the morning of 17 March, Imperial General Headquarters learned through intelligence channels that sizeable American fleet elements had quit Ulithi atoll in the western Carolines. It was assumed that the enemy task force was on its way to attack the Kyushu area. The attack was expected the following day.
Combined Fleet immediately alerted Fifth Air Fleet in Kyushu. The Air Fleet commander, Vice Adm. Matome Ugaki, was ordered to attack the enemy task force only if it contained invasion transports and to refrain from an engagement if it was composed exclusively of warships.50 Vice Adm. Ugaki, however, feared that, if he did not attack, he would lose his entire command on the ground. He therefore forwarded a strong recommendation to Tokyo that counteraction be taken regardless of the composition of the task force. The High Command forthwith released the local commander from the earlier injunction and instructed him to use his own judgement.51
At 2300 on the 17th, a Fifth Air Fleet search mission detected by radar a large enemy task force barely 250 miles southeast of the southern tip of Kyushu.52 Vice Adm. Ugaki immediately issued orders for a dawn attack in force. Even as this strike mission was taking off, enemy carrier planes were swarming in to hit air bases in southern Kyushu and Shikoku. Heavy damage was sustained.53
During the next four days, a violent air battle raged over the southern Homeland. Fifth Air Fleet threw into the battle a total of 193 aircraft, including 69 tokko planes. Losses were staggering, amounting to 161 planes, or 83 per cent of the total aircraft committed. These losses, together with the widespread havoc caused by enemy attacks on airfields, left the Air Fleet powerless to participate in further large-scale action for several weeks to come. On the other hand, the damage
inflicted on the enemy was believed so severe that any immediate invasion threat to the East China Sea area was considered drastically reduced.54
Preparations to meet eventual invasion were nevertheless carried forward vigorously. Every effort was made to assemble the planned strength of 4,500 aircraft in the battle theater as rapidly as possible. On 21 March, Sixth Air Army, which was still engaged in displacing its main strength to Kyushu, was placed under the command of Combined Fleet. The Commander-in-Chief, Combined Fleet, now exercised unified command over the bulk of all Army and Navy air units operating in the East China Sea area.55
While the Japanese strove to complete these preparations, the enemy continued his air and sea blockade of the home islands, hampering deployment for battle and constantly whittling down the overall war potential of the nation. Enemy B-29's continued their immensely destructive incendiary campaign, now concentrating on Nagoya, Japan's chief aircraft production center.56
Late in March, the Superforts began a surprising new series of attacks which wrought havoc in the Homeland rear area. On the 27th and the 31st, they carried out attacks on the Kyushu bases of the Fifth Air Fleet, closing down each field several days for repair.57 On the 27th and 30th, they sowed thousands of aerial mines in Shimonoseki Strait and the western Inland Sea, closing that vital supply artery for an entire week.58
Submarines and aircraft also continued to take their murderous toll of Japanese shipping. By the end of March, 74% of the nation's total merchant tonnage had been sent to the bottom, including 75% of the tanker fleet.59 As the
shipping crisis deepened, transport of essential supplies to the southern Homeland battle theater became almost impossible.
On 23 March, a strong Allied carrier task force suddenly attacked the island of Okinawa in the Ryukyus. This attack immediately appeared to cast doubt on the Fifth Air Fleet's battle claims of 18-21 March. The High Command, however, took the sanguine view that this was merely a minor operation, undertaken by the enemy while en route back to Ulithi in retaliation for the losses he had suffered off the Kyushu coast.60
This serious misjudgement was quickly exposed on 25 March when the enemy began to put ashore a landing force on the Kerama Islands, a small group about 25 miles southwest of Okinawa. On the same day, Combined Fleet issued an alert for the Ten-Go air operation.61
The situation was now precarious. The commitment of the Fifth Air Fleet on 18 March, far from having delayed the enemy invasion, had actually resulted in a premature and largely ineffective expenditure of Japanese air strength in Kyushu. The Sixth Air Army and the Third Air Fleet had not yet completed their westward displacement, while the Tenth Air Fleet was just beginning its specialized training.62 Air reaction to the landings in the Ryukyus was therefore negligible. On i April, when the enemy extended the amphibious offensive to Okinawa, the burden of defending that important island fell initially on the ground forces alone.63
The battle on Okinawa went badly from the very beginning. Handicapped by insufficient troop strength,64 Lt. Gen. Mitsuru Ushijima, commander of the Thirty-second Army, had concentrated the bulk of his forces on the southern portion of the island, where the terrain was relatively favorable to a strong defense. This, however, left the central sector of the island, containing two valuable airfields, virtually unguarded. The enemy landed directly in this weakened sector and quickly mopped up the small security detachments stationed there. Lt. Gen. Ushijima's forces to the south dug themselves in on strong battle positions in the Naha-Shuri area. By the end of the second week of the campaign, enemy forward elements began to approach this line preparatory to a show-down battle.
Although continually harassed by enemy air raids on the Homeland, Combined Fleet finally succeeded during the first week in April in effecting a partial concentration of air forces in Kyushu. Execution of the Ten-Go operation then began in earnest.
The decisive air battle began on 6 April with
PLATE NO. 146
an all-out effort by the air forces then available in the East China Sea sector. Participating units were the Sixth Air Army and Fifth Air Fleet in the Homeland, and the First Air Fleet and 8th Air Division on Formosa. Operating with the Fifth Air Fleet were attached units of the Third and Tenth Air Fleets, although the latter were in an exceedingly low state of training. Following the commitment of these units against enemy invasion vessels off Okinawa, it was planned to send out the last remnants of the Japanese surface fleet from the Inland Sea to attack survivors in the anchorage area.65
During the two-day period 6-7 April, the Japanese attacked enemy ships off Okinawa with a total of 699 aircraft, of which 355 were tokko planes. These attacks were boldly and vigorously carried out, and reported results were good.66
On the evening of the 6th, the Surface Special-Attack Force under Vice Adm. Seiichi Ito sortied from the Bungo Channel with one super-battleship (Yamato), one light cruiser, and eight destroyers in company. On the morning of 7 April, this force was spotted by enemy air reconnaissance while still over 400 miles north of Okinawa. A large part of the enemy's carrier plane strength, apparently undeterred by the Japanese air offensive, was unleashed against Vice Adm. Ito's force. In two strikes, one at 1240 and the second at 1345, the light cruiser and four of the destroyers were sunk. Yamato, hit by ten aerial torpedoes, went to the bottom at 1417, the second of Japan's two great 64,000-ton battleships to succumb to air attack. The four surviving destroyers returned independently to Japan.67
Between 12 April and 4 May, four additional large-scale air offensives were launched against the enemy fleet off Okinawa, the last of which was coordinated with the final all-out ground offensive of the Thirty-second Army During these operations, the Japanese air units flew a total of 1653 sorties, of which 761 were tokko missions.68
Although great successes were claimed by the participating units,69 the attacks did not have any noticeable effect on the local battle
situation. The Thirty-second Army ground offensive of 4-5 May made limited gains against exceedingly strong resistance, faltered, and fell back after a bloody two-day fight. Following this, Thirty-second Army was no longer capable of effective offensive action. Although the Ten-Go air operation was sustained for another six weeks, the enemy was securely in possession of Okinawa as a forward base after the failure of the 4 May offensive.70 All of Japan south of Tokyo, as well as Korea and the lower Yangtze, were now brought within easy range of enemy land-based fighters.
Just as the battle for control of the East China Sea area began, the Japanese High Command learned through intelligence channels that Soviet Russia had begun to redeploy troops from the European theater to the Far East. In Europe, the crossing of the Rhine by the Allied armies and the catastrophic defeats suffered by the Germans in the Saar and Ruhr valleys indicated that final collapse of Hitler's forces was imminent. Japan faced the dread of fighting the war alone.
Against the background of these alarming strategic developments, Homeland defense planning was hurriedly continued. On 20 March, Imperial General Headquarters Army Section transmitted to all major subordinate commands the preliminary draft of a voluminous operations plan to meet an invasion of the home islands. This document, based upon the general policy directive of 20 January, covered in considerable detail objectives, tactics and technique, troop movements, internal security, transportation, communications, and logistical administrative support. The draft was studied by subordinate headquarters, revised by the Army Section, and submitted to the Navy and to various governmental agencies for concurrence.71 On 8 April it was formally disseminated to the field commands. Its essential points were as follows:72
PLATE NO. 147
PLATE NO. 148
Concurrently with the publication of the Ketsu-Go plan, Imperial General Headquarters activated the headquarters of the First and Second General Armies according to previous plan, simultaneously deactivating the General Defense Command. (Plate No. 148) The First General Army under Field Marshal Sugiyama established headquarters in Tokyo and assumed command of the Eleventh, Twelfth, and Thirteenth Area Armies.80 The headquarters of the Second General Army under Field Marshal Shunroku Hata was established at Hiroshima and included command of the Fifteenth and Sixteenth Area Armies.81 To provide a similar command level for all Army air units participating in the campaign, an Air General Army headquarters was established under General Masakazu Kawabe. This headquarters took complete command of all Army air units in Japan and Korea,82 except the
Sixth Air Army which, until the completion of the Ten-Go operation, was to remain under the operational command of Combined Fleet. The organization of all these headquarters was completed by 15 April.
Meanwhile, the first general mobilization called for in the 26 February plan was successfully carried out. Thirteen new divisions, all of the coastal combat type, and one new independent mixed brigade were activated and assigned as follows:83
On 8 April, concurrently with the publication of the Kestu-Go plan, the High Command also issued the text of an Army-Navy Joint Agreement regarding ground operations. This document contained the following general provisions:84
Following the adoption of this joint agreement, the Navy, on 25 April, established a General Navy Command to exercise supreme operational control of all Navy surface and air forces. Admiral Soemu Toyoda, Commander-in-Chief of Combined Fleet, was designated Commander-in-Chief, General Navy Command, holding both positions simultaneously.86 (Plate No. 149)
The wholesale mobilization of the national potential required to implement the Ketsu-Go plan obliged Imperial General Headquarters to give the nation frank warning that the Japanese home islands, inviolate through centuries, now stood in imminent peril of feeling the tread of an invader's heel. This dread prospect evoked in the Armed Forces and civil population alike a readiness to take the most extraordinary measures to repel the enemy.
The national attitude became the basis of tactical policy This was gradually elaborated in many official directives, guidance manuals and public announcements issued to implement the Ketsu-Go plan. The general concept of Homeland defense set forth in these documents was as follows:87
PLATE NO. 149
Under this general scheme of tactics, the chief burden of blunting the American invasion spearhead fell upon the air and sea special-attack forces. However, the application of the tokko principle was to be carried much farther than ever before. For the first time in the war, tokko methods were to be used in ground combat on a large scale, by both formal military organizations and partisan groups.
In land combat operations, the tank was the enemy's most effective weapon, especially when equipped with a flame-thrower. It was therefore expected that large armored formations would be used in the Homeland invasion. The Japanese forces were ill-equipped to meet such an attack due to marked inferiority in both tanks and antitank guns.90 This made
it essential to develop an aggressive antitank program relying on other weapons.
Experience in the Philippines and on Okinawa had demonstrated that the only effective means of combatting enemy tank superiority lay in a resort to mass special-attack operations. Manuals and directives issued to implement the Ketsu-Go plan therefore placed strong emphasis on the utilization of such tactics. All military units, as well as civilians, were to be trained in the use of the many different types of hand-carried mines and charges designed for such attacks.91
Second only to the emphasis laid on tokko tactics, the most important aspect of the Ketsu-Go plan and its implementing directives was the inclusion of the doctrine of an aggressive beach defense. This doctrine, in brief, called for the defending forces to make their decisive stand on the beach and in the coastal plain rather than on inland positions, no matter how favorable in theory the latter might be. The decision to do this stemmed from the following considerations:92
The third unique feature of the Ketsu-Go plan was the extent to which the civilian population was to participate in the actual military defense of the Homeland. The plan called for a "National Resistance Program," the basic concept of which was that all able-bodied Japanese, regardless of sex, would be called upon to engage in battle.93 Should the enemy overrun any considerable part of the Homeland, his forces were to be beset from all sides by partisan operations. Each citizen was to be prepared to sacrifice his life in suicide attacks on enemy armored forces. In addition, civilians were to be used in large numbers for behind-the-lines duties such as air raid precautions, construction, transport, and evacuation.94
Thus, relying for the most part on the suicidal bravery, ardent patriotism, and fierce loyalty of the people, Japan prepared to wage the final decisive battle against an enemy far superior in both technical resources and manpower.