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The U.S. atomic bombings of Hiroshima (August 6, 1945) and Nagasaki (August 9, 1945), acts which killed over 200,000 people (mostly civilians) forced Japan’s unconditional surrender, effectively ending World War II.  President Truman’s decision to employ atomic weapons was not taken lightly, and was controversial at the time, and is perhaps even more so today.  However, it was clear that the U.S. high command felt that it had no choice but to commit the atomic bombings, as they sincerely believed that the alternative was dramatically worse.  The present document, in frightful detail, describes the alternative.

 

Through 1944, it was clear to all that Japan was on the backfoot in World War II, unable to defend its massive, sprawling conquered territories.  However, despite being forced into continual retreat, the Japanese always fought hard, making the Allies pay dearly for every mile of gains in blood and treasure.

 

After bettering Japan in New Guinea and various southwestern Pacific islands, the U.S. spearheaded the Philippines Campaign (October 20, 1944 – August 15, 1945).  While the Americans and their Filipino allies were able to gradually liberate the country, the fighting was horrendous, as the Japanese simply refused to surrender, regardless of their losses or suffering.  In the end, the Americans lost over 20,000 men in the Philippines versus the Japanese death toll of 420,000!

 

The Japanese resolve to fight the to the bitter end was underscored when the Americans first brought the war to Japan proper.  At the Battle of Okinawa (April 1 – June 22, 1945), the U.S. mounted the largest amphibious assault ever endeavored in the WWII Pacific Theatre, landing upon the main island of the Ryukyus, located about 550 km for the Japanese Home Islands.  During the eight-week long contest, as many as 250,000 American and British troops squared off against 77,000 Japanese regulars and 40,000 local conscripts.  The Japanese forces fought tooth and nail, employing thousands of kamikaze (suicide) tactics by aircraft, boats and individuals.  The fighting was described as some of the most brutal of all modern conflicts and was the bloodiest battle fought the Pacific Theatre of the war.  While the Allies prevailed, they lost 50,000 men, while the Japanese lost 100,000 fighters and as many 150,000 Okinawan civilians – a massive death toll on an island of 575,000 residents!

 

Instead of feeling triumphant or closer to ultimate victory, the U.S. High Command was chastened by the astounding casualty rate of Okinawa, fearing that it would set a precedent for the war going forward.

 

At the First Quebec Conference (August 19-24, 1943), where the Western Allies met to plot overall war strategy, it was discussed that the invitation of the Japanese Home Islands was not likely to occur until 1947-8.  At the sequel meeting, the Second Quebec Conference (September 12-6, 1944), Roosevelt and Churchill secretly made plans to use atomic bombs upon Japan, to expedite the end of the war.  However, the ‘Manhattan Project’ which would enable this, was kept as an ultra-secret, unknown to almost all U.S. commanders and even Vice President Truman.  As such, the U.S. High Command and war planners continued to work under the assumption that the war in the Pacific would end with an invasion of Metropolitan Japan.

 

By January 1945, a planning committee led by General Douglas MacArthur and Admiral Chester Nimitz had devised Operation Downfall, the Allied mega-campaign to invade the Japanese Home Islands.  They operated under the assumption that the surrender of Japan must be secured within year after the fall of Nazi Germany (which was only months away) – at the latest, as the American public would not have the stomach to continue the war beyond that point, let alone the matter of what would be the falling morale of GIs (something that the Japanese were banking on).

 

Operation Downfall was to have two distinct but related parts.  Operation Olympic was to see Allied forces land on Kyūshū (using Okinawa as a base), taking the southern third of the island only, to serve as a base for continuing the campaign.  This endeavour was to be launched on X-Day on, or around November 1, 1945.  If Operation Olympic was successful, the Allies planned to enact the second part of the Operation Downfall, being landings on the Kantō Plain, near Tokyo, dealing a death blow to the enemy, in what was would be known as Operation Coronet (which was planned to occur on, or around March 1, 1946).

 

X-Day would require the largest armada ever assembled, as it was planned to involve 42 aircraft carriers, 25 battleships, 400 destroyers and hundreds of troop transports and support vessels.  It was also to include 14 army divisions and 3 separate air force armies accounting for 25% of all available Allied air power worldwide.  Operation Olympic was to engage over 700,000 troops and 136,800 land vehicles.  It was initially planned that the Allied forces would outnumber the Japanese defenders by 3:1 (although this ratio was always wildly optimistic).

 

The X-Day landings were to occur at three locations on the south Kyūshū coat, at Miyazaki, Ariake, and Kushikino, with the 35 designated beaches for deployment named after automobiles (ex. Buick, Cadillac, etc.).  As a feint, the Allies would try to convince the Japanese they their true target was Taiwan, a diversionary tactic known as Operation Pastel.

 

However, Japan had a plan, anticipating the Allied juggernaut – Operation Ketsugō (決号作戦, ketsugō sakusen) (‘Operation Codename Decisive’).  Japan, which always had high troop levels concentrated in heavily fortified bases in southern Kyūshū, was prepared to stop the Allies cold with a force brought up to as many as 990,000 men, supplied with 40% of all Japan’s available weaponry.  A propaganda campaign was to be launched calling for both soldiers and civilians to sacrifice their lives to protect Japan under the banner ‘The Glorious Death of One Hundred Million’.  For this cause, over 10,000 aircraft were dedicated for use by July 1945 (with more being made for use in the autumn), while hundreds of specially designed kamikaze boats were built with the objective of destroying much of the Allied landing force before it even reached Kyūshū’s shores.  In short, the Japanese had a good idea of what the Americans were planning and were ready and waiting.

 

By the early summer of 1945, the planning for Operation Olympic had reached a very mature stage, with the alternative of dropping atomic bombs on Japan remaining a closely guarded secret, unknown to virtually all those planning the landings.  General Douglas MacArthur, who was to be the Commander-in-Chief of the campaign, selected the U.S. Sixth Army to spearhead Operation Olympic, a force which had served him so well for the last 2½ years.

 

The Sixth Army was formed in January 1943, developed out of the ‘Alamo Scouts’, a legendary commando unit based in San Antonio Texas, such that the army was popularly known as the ‘Alamo Force’.  Led by the ultra-reliable General Walter Krueger, the Sixth Army fought brilliantly in the New Guinea Campaign and was the driving force behind successful but grueling effort to reconquer the Philippines from Japan.  The Alamo Force was both tough and smart, and in the Philippines its G-2 Section (a division level military intelligence agency) had distinguished itself as one of the world’s finest military field intelligence operations, often uncovering the best kept Japanese secrets at just the right time.

 

The Sixth Army’s G-2 Section was led by Colonel Horton Vail White (1901 – 1963), a wily Nebraskan career officer who served as the Alamo’s Force’s Assistant Chief of Staff.  His chief deputy of the intelligence was Lieutenant Colonel Frederick W. Bradshaw (1905 – 1946), a prominent Jackson, Mississippi lawyer with no military experience, who was suddenly pulled out of upon by greatly impressing General Krueger during a visit to an officer training camp in Louisiana.  From November 1943, Bradshaw led the Alamo Scouts Training Center (ASTC), in New Guinea, which was famed for its rigorous commando course, before being selected to be the deputy head of intelligence for the Sixth Army.  The present document comes from his estate.

 

Importantly, not only was the Sixth Army to spearhead Operation Olympic, but White and Bradshaw’s G-2 Section was to play a leading role in intelligence gathering and analysis for the endeavour.

 

In July 1945, the Sixth Army’s G-2 Section submitted a pre-action assessment report to MacArthur on Operation Olympic, drawing on the knowledge of Japanese capabilities and tactics learned during the Battle of Luzon.  Here it was which predicted that the Japanese already had over 400,000 well-entrenched troops ready to meet the Allies in southern Kyūshū, and that due to both conventional and kamikaze tactics, the Allies would suffer 124,935 casualties within the first 120 days of the operation.

 

Meanwhile, other U.S. intelligence assessments predicted that Operation Olympic would result in over 200,000 Allied casualties within a short time, and that Operation Coronet would result in over 400,000 fallen soldiers.  Some even predicted that 1 million Allied troops would die in the first nine months of the invasion of the Japanese Home Islands.  Moreover, it was widely accepted that Operation Olympic would result in the deaths of 1.1 Japanese civilians in Kyūshū, while Operation Coronet would see 5.1 million non-combatants perish in the Kantō Plain region.  Moreover, the Allies were also concerned that during the invasion, the Japanese Army would murder the 285,000 Allied prisoners (170,000 POWs and 115,000 civilians) held on the islands.

 

Regardless of which intelligence assessments one believed, any Allied invasion of the Japanese Home Islands promised be an epic bloodbath, that would stress Allied capabilities and morale to its breaking point, not to mention the unprecedented atrocity that would befall the Japanese people.

 

Due to this blood-chilling intelligence, President Truman made the decision to drop atomic bombs upon Japan to bring a rapid end to the war by forcing Japan’s unconditional surrender.  While employing atomic weapons was horrific, Truman was left with a ‘Sophie’s Choice’, whereupon he chose the route that would seemingly lead to the least military and civilian deaths, although the merit of his decision has been hotly debated ever since.

 

On August 6, 1945, an atomic bomb was dropped on Hiroshima, while Nagasaki was struck three days later.  Amazingly, although the Americans made it clear they would keep atomizing parts of Japan unless it promptly yielded, it took almost a week after Nagasaki for Emperor Hirohito to announce Japan’s unconditional surrender, and it was not until September 2, 1945, that the capitulation was signed.  Japan’s reticence to surrender, even in the face of certain doom, was in line with the belief that its military and civilian population would fight to the last man had the Allies carried out Operation Olympic and Operation Coronet.

 

The Present Report in Focus

 

Following Japan’s surrender, the county was placed under U.S. military occupation.  The U.S. Sixth Army was deployed to help fulfil this mandate, setting up its headquarters in Kyoto.

 

Importantly, during this period, the Sixth Army’s G-2 Section was given the important task of creating the definitive report on the actual Japanese designs to counteract Operation Olympic (being Operation Ketsugō), resulting in the present ‘The Japanese Plans for the Defense of Kyushu’.

 

While Operation Olympic and Operation Ketsugō would never occur, living on only in the realm of ‘counterfactualism’ (What if?), the U.S. military high command felt that it was critically important to fully understand what the Japanese knew of the Allied plans and what they had prepared to defend Kyūshū, as well as the outcomes they predicted.  This was an imperative for several reasons.

 

First, it allowed the U.S. High command to assess the performance of its own military intelligence apparatus (How closely did the U.S. assessments of the Japanese preparedness match with reality?; How well did the Americans do in ensuring that their plans were not revealed to the enemy?).  Knowing the answers to these questions would allow the U.S. to improve is military intelligence capabilities in the next major war.

 

Second, as the U.S. was now indefinitely responsible for defending Japan, the methods used by the Japanese to counteract a full-scale invasion could serve as useful lessons for the Americans in light of the emerging Cold War, in the event that they had to defend the islands from an assault by the Soviet Union (which incidentally considered invading Hokkaido near the end of World War II), or another major adversary.

 

Third, a definitive report on Operation Ketsugō would prove that Operation Olympic, and indeed Operation Downfall in general, would be astoundingly costly in both Allied and Japanese lives (dramatically more so than dropping a couple atomic bombs), so justifying (both morally and practically) the American decision to atomize Hiroshima and Nagasaki.

 

Fourth, MacArthur and his top officers must also have simply been curious about a matter that occupied months of their time, leading to so many sleepless nights.

 

Colonel White and Lt. Colonel Bradshaw then led a grand intelligence operation to shed light upon the actual nature of the preparations for Operation Ketsugō, and what the Japanese knew or guessed about Operation Olympic.  Most importantly, they were able to interview numerous (now captive) Japanese officers who were directly involved in planning Operation Ketsugō or had otherwise gained privileged knowledge of the design.  These efforts proved highly successful, as many of the Japanese officers seemed happy to candidly discuss Operation Ketsugō, perhaps out of seeking release from the war, gaining the favour of their captors, or maybe even out of a sense of pride for having organized what would have been an awesomely impressive defensive plan.

 

Much of the draft material in the report appears to have been created while the Sixth Army was still based in Kyoto, before it moved its headquarters back stateside to San Francisco, in early December 1945.  It seems that some or all the maps that illustrate the report, which were published in a very crude print quality, with very faint hectographed overprinting, were likely issued from a mobile army press in Kyoto, while the final text and the compilation of the work was executed in San Francisco, dated from the last day of 1945.

 

The present report was classified as ‘Restricted’ and would have been made in only a handful of examples for the eyes of only senior staff officers, as well as some civilian planners, intelligence officials and political figures.  Indeed, it contained many details about how to defend Japan from an amphibious assault that the U.S. would not want the Soviets or Red Chinese to learn.  Indeed, these concerns persisted throughout the Cold War, such that the report was not fully unclassified until 1998!

 

Not surprisingly, the present report is today extremely rare, as it would have been issued in only handful of examples for high-level use, while many examples would have been intentionally destroyed owing to their classified nature.  We can definitively locate only 2 institutional examples, held by the Ike Skelton Combined Arms Research Library (Fort Leavenworth, KS) and the within the John Tolson Papers at the U.S. Military History Institute (Carlisle, PA).  Additionally, we believe, but cannot confirm, that there is likely an example held by the U.S. National Archives (perhaps as part of the collections of ‘Records of Sixth Army’: 338.9.6. or ‘Records of General Headquarters Southwest Pacific Area’: 338.5.9).  Moreover, we are not aware of any other examples of the report as having ever been offered on the market.

 

The present example of the report has an august provenance, coming from the papers of Lt. Col. Frederick W. Bradshaw, the Mississippi lawyer, legendary commando trainer and spymaster, who served as the deputy head of the Sixth Army’s G-2 Section.

 

As will be revealed below, once fact took the place of speculation, it was inarguable that Operation Ketsugō would have been a terrifying ordeal for the Allies.  The Japanese were well prepared and committed to extreme measures, had a stellar understanding of the Allies’ intentions for Operation Olympic and were in no way fooled by the Americans’ diversionary tactics (i.e., Operation Pastel).  The present report would have confirmed the Allied commanders’ worst fears.  On a positive note, it also revealed that the Sixth Army G-2 Section’s July-August 1945 intelligence assessment of Japanese preparations for the defense of Kyūshū was amazingly accurate.  The report makes for a fascinating read, confronting one of the great questions of counterfactualism in modern history.

 

The report provides an amazingly accurate, complete and meticulous view of Operation Ketsugō, revealing the exact nature, size and locations of all Japanese forces on Kyūshū, along with their capabilities and tactics, with exact accounts of their fortifications, equipment, arms, ammunitions and provisions.  The text of the report is divided into an introduction by Colonel H.V. White (the main author/editor of the final text); Part I, a lengthy Q&A based on interviews with officers of the Japanese Second General Army; Part II, intelligence from interviews with officers of the Japanese 40^th and 57^th Armies; and then concluding with Annexes featuring 2 charts and 5 custom maps.

 

Delving into the report itself, we feel it is best to relate Colonel White’s introduction to the report in its full and unmodified form, as the study’s purpose and content could not possibly be better summarized:

 

By the end of July 1945, sufficient information was available for the G-2 to make a preliminary estimate of the enemy strength in KYUSHU.  In the Sixth Army G-2 estimate for the OLYMPIC operation, dated 1 Aug­ust 1945, it was estimated that 421,000 Japanese troops were on KYUSHU, comprising nine divisions (or division-equivalents), plus a large num­ber of base and service troops, and naval personnel.  Subsequent infor­mation, obtained prior to the end of the war, including new identifi­cations and estimated reinforcements, raised the estimated total to 680,000, including fourteen divisions (or equivalents).  This figure  was reached just prior to the end of the war.

 

Information secured since the occupation of JAPAN reveals that the overall total strength on KYUSHU of Japanese units of all services and  types as of the final day of hostilities totaled approximately 735,000, including fourteen divisions and seven independent mixed brigades.  However, this total includes units on the islands off-lying KYUSHU, which were not included in the Sixth Army estimate of the situation.  Strength on these islands totaled approximately 25,000 and included three independent mixed brigades.  Thus, the Sixth Army’s 1 August es­timate was based on information procured in May, June, and July, and full allowance was made for large scale reinforcement, while the pro­jected (but never published) revised estimate with complete information was 96% accurate.  The discrepancy in 1 August estimate was largely caused by the underestimation of naval ground troops, whose number was  greatly swelled by recruits undergoing boot training and by crews from ships which had been immobilized by allied attacks, and from troop units in transit.

 

The Japanese expected our invasion of the home islands, they expec­ted it to be made during or after October 1945, they expected it to be made in southern KYUSHU, and that our landings would be made on the beaches of MYAZAKI, ARIAKE-WAN and SATSUMA PENINSULA.  Their avail­able combat forces had been deployed according to these expectations, with reserves being strengthened when hostilities ceased.

 

Allied convoys approaching KYUSHU would have received mass suicide attacks by every available plane in the KYUSHU area.  Transports would  have been the main targets of these attacks, and the Japanese expected to destroy 10% in this manner.  Offshore, the landing forces would have been hit by large numbers of small suicide craft and submarines, and the Japanese expected to destroy 60 transports by these means.

 

Once a landing or landings were made, a decisive stand would have been initiated.  Placing much stress on artillery, and having three tank brigades, one independent tank company, one independent regiment, and four self-propelled gun battalions to support division troops in their operations, the Japanese forces planned to make a final stand near the beaches and units were instructed to remain in place until an­nihilated.  Heavy counter-offensives in the beach areas were planned and little preparation was made for defense in depth.

{signed: H. V. WHITE, Colonel, G.S.C., AC of S, G-2}.

1. Information as Prepared by Members of the Staff of the Japanese Second General Army (pp. 1-15)

This section commences with the lines: “The following information on the defense of KYUSHU was obtained as the result of a directive sent to the Japanese Second Demobilization Headquarters (formerly the Japanese Second General Army) … [which] was directed to submit accurate and complete information on the nature and extent of the Japanese preperations for the defense of KYUSHU at the time of the surrender, such in­formation to be obtained exhaustively from all sources, including when necessary the memory of subordinate unit commanders and staff officers.”

There then follows a fascinating and thorough Q & A, featuring 33 Questions (many with multiple parts).  The ‘General’ questions and answers, which set the scene, include:

1. Q: Were Allied landings on KYUSHU anticipated? If so, when, where and in what strength?

A: The landing of the Allied Forces on KYUSHU was anticipated.  Allied strength was estimated at 300,000, and three areas in southern KYUSHU (namely the MIIAZAKI, ARIAKE BAY and SATSUMA PENINSULA areas, where landing would be enforced either simultaneously or in succession) were designated as points of landing, the time of which was predicted to be during Autmn (October) or later.

2. Q: What intelligence of Allied intents did the Japanese High Command possess? Specifically what was known and what was the source of this knowledge? Prisoners of war? Captured documents? Special operatives? Aerial reconnaissance and photography?

A: Various strategic information for judging Allied intents were controlled by.the Imperial Headquarters, and from this informa­tion deductions were made and issued to armies under direct control.  The Second General Army directed its efforts towards gaining intelligence of the military tactics involved in the minute details of the landing points, dates and strength of the Allied Forces based on the strategic deductions of the Imperial Headquarters.  The methods for gaining this intelligence were: movement of controlled planes (re­connaissance and photography); observation of frequency and direction of U.S. bombing and reconnaissance within army area in the form of statistics, and study of movement of task forces and of the develop­ment of international affairs, expecially that of American public opinion (through radio reception).  The main points of issue in the handling of information were: The problem whether the Allied Forces would conduct operations on the CHINA coast prior to their landing on the home islands, or whether SAISHU-TO and southern KOREA would be used as intermediary battle points when the home islands were attacked directly.  However, mainly due to the progress of the PHILLIPINES and OKINAWA campaigns, the conclusion as mentioned before, that the south­ern part of KYUSHU would be the first landing area, was reached.

3. Q: Was it supposed that the Allied landings on KYUSHU were to constitute the main effort against the Japanese homeland or to be pre­liminary to larger efforts elsewhere?

A: The Allied landings on KYUSHU were reasoned as prelimin­ary tactics to the main operations against the KANTO area.

4. 4. Q: Was it supposed that the Allied landings on KYUSHU would precede, follow, or occur simultaneously with landings on the CHlNA coast?
5. The landings on KYUSHU were judged as taking place prior to the operations on the CHINA coast. Judging from the landing dates and reserve strength of the Allied Forces, it was thought impossible for the CHINA and Japanese HOME ISLAND operations to be conducted simultaneously, while the American strategic situation apparently lacked the need for conducting operations in CHINA, only resorting to aid tactics for political effects.
6. 5. Q: At what time, if at all, was it anticipated that Formosa would be by-pased?

A: Operations against TAIWAN (FORMOSA) were thought very improbable after the OKINAWA operations.

Questions 7 to 11 provide detailed intelligence on Japanese troop strength and its identity and distribution, as well as the time sequencing of the positioning of the Japanese forces in Kyūshū.

Regarding ‘AIR DEFENSES’ (Questions 12-18), some highlights of the Q&A include:

12. 12. Q: How many combat-type planes would have been committed to the attack on amphibious units of the Allied landing forces, how would these have been employed (that is, in kamikaze, high and low level bombing, dive-bombing, torpedo bombing, or baka-launching tactics), and what percent would have been held in reserve for use against later invasion forces?

A: The number of bombers which would have been employed to attack Allied landing units was about 800, of which most were special at­tack types (kamikaze).  Storming planes, bombers and fighters would have, been ultimately transformed into crash-landing planes…

In ‘Naval Defenses’ (Questions 19 – 23) there is much detail on the Japanese mines, ships and submarines, as well as plans to attack U.S. transports by kamikaze methods.

As for ‘Ground Defenses’ (Questions 24 – 30), there is coverage of anti-tank tactics, armored units, chemical warfare (The Japanese decided not to attempt these methods, fearing the Americans could overwhelm them in this regard); artillery; coastal guns; anti-aircraft guns; and mines.

In ‘Tactics’ (Questions 31-32), it clear that the Japanese essentially anticipated where the Allies were going to land and were ready for them.  Some highlights of the Q&A are:

Q: [31] a. Which of the following beach areas were considered most vulnerable to attack and which were best defended: (1) MIYAZAKI, (2) ARIAKE, (3) MAKURAZAKI, (4) KAGOSHIMA and (5) KUSHIKINO?

1. The MIYAZAKI coast, the front of ARIAKE BAY and the coastal area between KUSHIKINO and MAKURAZAKI were given equal consideration as mutual points of operation. However, the degree of defense at the date of surrender, owing to the time element, showed the ARIAKE BAY front to be first and the in MIAZAKI coast second in degree of readiness. (In the first part of October, the three district areas were scheduled tobe fortified to an equal degree).

Q: [31] c. Would a strong defense have been made on the beaches?  If so, in what strength, with what tactics, and supported by what kind of fixed installations?

A: powerful defense was established directly near coastal areas.  One third to one fifth of the whole coastal defense strength was stat­ioned along the beaches.  The beach defenses were uniformly strong; where natural terrain features were advantageous for defense less troops were stationed, but poor defensive terrain was defended with greater strength.  The principal fighting method and object of coastal stationed units was to persistently destroy the establishment of beach heads (airfields), and to enforce continuous counter-attacks in wave formation to attain the same.  For this purpose fighting units would take their stand even to utter annihilation.  Camps were basically established underground or in caves.  Weapons were set up for last-ditch defense against allied fire and bombardment.

Q: [31] f. Would the strategy on southern KYUSHU have been designed to achieve delay or annihilation?

A: The action in southern KYUSHU was for the purpose of thorough annihilation.

1. Q. [31] i. Would the southern KYUSHU forces have been committed to defend to the death, in place, or had arrangements been made for their possible retreat?
2. All units in southern KYUSHU were given orders to defend to the death and retreat was not recognized as a possibility.

The ‘Hospitals and Supply’ section (Question 33, which has many parts), details the Japanese medical support for Operation Ketsugō, plus noting reserves of provisions and ammunition, etc., in all indicating that the Japanese were well supplied.  The Japanese had “One month’s provisions for 2 million men and 80,000 horses … while reserves for further operations in KYUSHU, namely, one month’s provisions for 1 million men and 110,000 horses, were to be diverted from HONSHU.”  Also, they had sufficient fuel and ammunition to terrorize the Allies for some time.

As for ‘Medical’ provisions, “The projected amount was one month’s supply for 6 million troops, of which enough for 4 million were supplied to each Army (corps) for coastal warfare, while supplies for 2 million were retained as reserves.”

1. Q. [33] How long was it beleived that the Japanese forces could continue effective resistence in KYUSHU from a supply standpoint?

A: The probable lengths of time for continued operationin KYUSHU viewed from the standpoint of replenishment of ordnance and am­munition were judged as follows:

(a) In event of possible replenishment from HONSHU – 3 months.

(b) In the case of impossibility of replenishment from HONSHU – 2 months.

(c) The continuation of protracted warfare was judged pos­sible by maintenance of northern-KYUSHU mountain areas.  For that reason a synthetic underground factory for ordnance and ammunition was under construction on the vicinity of HIDA.

1. Notes from an Interview by V Amphibious Corps and Allied Officers of the Commanding Generals and Staff Officers of the Japanese 40^th and 57^th Armies (pp. 16-20)

This section commences by noting that “The 40th-Army was responsible for the ground defense of southeastern KYUSHU.  The Japanese extimate of the situation was that enemy landings in force could be expected any time after 1 October 1945 in the areas of KUSHINKO, ARIAKE-WAN and KIYAZAKI.  It was also considered possible that landings might take place on the southern coast of the SATSUMA PENINSULA, particularly on the beaches immediately to the west of LAKE IKEDA…

The initial intention was to prevent the enemy from obtaining a proper footing ashore.  This was to be done by the coastal divisions in­flicting the maximum amount of damage on the enemy in the vicinity of the beaches themselves.  After the initial-assault had been held by the coastal divisions, the strongest possible counter-attack was to be de­livered by reserve forces concentrated for the purpose.

It was intended to prevent enemy shipping from entering KAGOSHIMA­-WAN.  The Japanese considered that entrance to KAGOSHIMA-WAN might be attempted either by enemy ships forcing an entry through the minefield covering the entrance, or initially taking the LAKE IKEDA area by a landing from the south and then capturing the guns covering the straits.”

There is then a great deal of detail given as to all the participating Japanese divisions and their locations.

It is noted that “No general directive had been issued to the coastal divisions re­garding the tactics to be employed in beach defense.  However, the de­fense depended mainly on localities, prepared for all-around defense, sited in depth and mutually supporting, as far as ground would permit.  The main localities were of approximately battalion strength, other localities of approximately company strength.  In addition to these de­fended localities, the various battalions had forward elements in fox­ holes and trenches at the back of the beach, to act as look-outs to send information back to the main localities and to provide suicidal opposition to the initial landing.  The majority of these forward positlons were apparently sited on forward slopes with good fields of fire onto the assault beaches.

If available, land mines were to be employed in beach defenses, but there seemed little likelihood of supplies forthcoming.  No plan existed for the employment of under-water obstacles on the beaches…

The main tank strength was to be concentrated in the area of LAKE IKEDA, and was to be employed in a non-mobile role, the tanks being dug-in and used purely as anti-tank artillery…

Artillery would be located in rear areas, covering the Japanese be­tween defended localities and with ability to fire on the beaches…

When the landings took place, civilians were to evacuate the for­ward areas and were to be organized for employment in company supplies, repairing roads, etc., in the rear areas.”

Concerning the 57^th Army, much detail is provided on the formations and locations of its forces.

It is written that “The Japanese plans for the defense of southern KYUSHU were based on the assumption that the American landings in strength would take place simultaneously in the areas of MIYASAKI, ARIAKE-WAN and KUSHINKO.  In addition, it appeared from the 40^th Army plans, that considerable im­portance was attached to the possibility of a landing in the areas of MIYASAKI, ARIAKE-WAN and KUSHINKO.  In addition, it appeared from the 40^th Army plans, that considerable importance was attached to the possibility of a landing in the MAKARUSAKI area.  In light of this overall plan, the 57^th Army had placed its main strength in the MIYKAKI PLAIN area.”

There then follows a great deal of information on the tanks, etc. that the 57^th intended to employ.

It is noted that the “Divisions alloted to coastal defense were committed to a policy of annihilation of the invader within the beach-head area.  No general di­rectives as to how such a defense should be conducted had been issued either by the 57^th Army or by any higher command.

Within each regimental area on the coast, the first line of resistance which the invaders would meet would be a thin screen, of infantry dug-in among the dunes at the back of the beach in foxholes and tunnels.  It was hoped that a per­centage of these troops would survive the preliminary bombardtnent and offer a certain amount of suicide resistance to the first wave of in­vading forces, and also send back some information to the defended lo­calities behind.  Behind the line of dunes, positions were prepared, for all-around defense, from which considerable resistance could be offered.  The kernel of the defense, however, was still farther back in completely prepared positions, almost invaribly selected on high ground.  Such positions were to be occupied by the equivalent of a battalion group strength and were to be defended to the very end.”

ANNEXES (5 Maps, 2 Charts):

 

[1] Annex “A” [Part 1].

‘Status of Kyushu Units at Time of Surrender’

Chart: typescript, 2 pp.

 

This important chart methodically lists and details all aspects of the Japanese forces that were onsite in Kyūshū for Operation Ketsugō, with categories for Area (general part of Kyūshū), units, strength (exact troop numbers), location (precise placement).

 

[2] Annex “A” [Part 2].

Outline Map of Kyushu / ‘Disposition of Japanese Forces on Kyushu at Time of Surrender’ / Prepared By A.C. of S., Hq. Sixth Army, Annex “A”.

Map: photolithograph with purple and yellow hectographed overprinting, 50.5 x 57 cm.

 

This map, marked as ‘SECRET’ in the upper margin, graphically illustrates Annex “A”, Part I, showing the rough locations of the various listed army units by employing hectographed overlays of conventions of flags with the appropriate markings and identification numbers.

 

[3] Annex “B”.

Japan (South) Special Map, Annex “B”.

‘Reproduced by 650^th Engineering Bn., Sixth Army, August 1945.’

Map: photolithograph with purple hectographed overprinting, 49.5 x 57 cm.

 

This general map of southern Japan is overlaid with in purple hectography with the locations of maritime minefields and anti-submarine constructions in the seas off Kyūshū and southwestern Honshu.

 

[4] Annex “C”.

Sketch Map of Western Japan / ‘Strategic Japanese Reserves for Southern Kyushu Operations’ / Prepared By A.C. of S., HQ. Sixth Army, Annex “C”.

‘Reproduced by 650^th Engineering Bn., Sixth Army, October 1945.’

Map: photolithograph with purple hectographed overprinting, 49.5 x 57 cm.

 

This map of western Japan is overprinted with details as to the locations and identity the reserve forces variously on Kyūshū, Honshu and Shikoku, that were positioned to reenforce the Japanese forces on Kyūshū in the event of Operation Ketsugō.  They are classified as ‘Primary’, ‘Secondary’, ‘Tertiary’, and ‘As Situation Develops’.

 

[5]

Annex “D”.

‘Plan of Main Ammunition Concentrations in Kyushu’

Statistical Table: typescript, [2 pp.].

 

This statistical table details the ammunitions available to the Japanese forces for Operation Ketsugō to be used for various weapon types and designed for use by specific parts of said forces.  It is composed of vertical columns: ‘Variety’ (# of rounds, for ex. gun ammunition, heavy grenades, infantry guns, mountain guns, trench mortars, and howitzers, etc.); ‘Concentration Amount’; ‘Direct Control by 16^th Army’; ‘Direct Control by 57^th Army’; ‘Direct Control by 40^th Army’; and ‘Direct Control by 56^th Army’.

 

[6]

Annex “E”.

Kyushu / Headquarters Sixth Army AOP 442 / Office of the A.C. of S., G-2 / ‘Main Supply and Strategic Routes for Kyushu Operation’, Annex “E”.

Reproduced by 69^th Engr. Topo. Co. July, 1945’

Map, photolithograph with purple and pink hectographed overprinting, 33 x 42.5 cm.

 

This transportation map depicts the main supply and strategic routes to be employed by the Japanese for Operation Ketsugō, as overlaid in purple and pink hectographed lines, which according to the legend, lower right, identifies main railways; two-way traffic for motor cars; one-way traffic for motor cars; and pack-horse routes.

 

[7]

Annex “F”.

‘Japanese Plan of Defense / Kyushu Island / Adapted from sketch prepared by A.C. of S., G-2’, Annex “F”.

Map, photolithograph with purple and pink hectographed overprinting, 33 x 42.5 cm.

 

This very detailed map employs hectographed overlays to show the exact distribution of all the units of the Imperial Japanese Army in Kyūshū as positioned for Operation Ketsugō, labeling their locations and showing the boundaries between the operational zones of the ‘General Army’; ‘Mid-Army’; ‘Divisions’; and ‘Regiments’.  As noted in the main text on page 20: “A Sketch prepared by the A.G. of S., G-2, V Amphibious Corps gives a good illustration of the Japanese plan for the defense of KYUSHU (see Annex F)”.

 

Tipped into the report is a letter from General Walter Krueger, the commander of the Sixth Army, dated January 20, 1946, in the form of a “Memorandum”, addressed to “Each member of the Sixth Army Staff”.  Here he writes: “Upon the inactivation of the Sixth Army on January 20, 1946, you will be able to look back with justifiable pride upon your service as a member of its staff and upon your share in its outstanding achievements… It is with real affection that I bid you farewell, good luck, and Godspeed.”

 

References: Ike Skelton Combined Arms Research Library (Fort Leavenworth, KS): N12785; John Tolson Papers, U.S. Military History Institute (Carlisle, PA); OCLC: 464581223; Barton J. BERNSTEIN, ‘The Alarming Japanese Buildup on Southern Kyushu, Growing U.S. Fears, and Counterfactual Analysis: Would the Planned November 1945 Invasion of Southern Kyushu Have Occurred?’, Pacific Historical Review, vol. 68, no. 4 (1999), pp. 561–609; D. M. GIANGRECO, Hell to Pay: Operation DOWNFALL and the Invasion of Japan, 1945–1947 (2017), Appendix B; Robert P. NEWMAN, Truman and the Hiroshima Cult (1995), p. 204; Stephen J. ZALONGA, Defense of Japan 1945 (2011), p. 62.