As early as January 1945, the Imperial Japanese Army and
Navy reached agreement (although their cooperation was, as always, limited by
inter-service rivalry) on Ketsu-Go (“Operation Decision”): the final defence of
the Japanese home islands against Allied invasion. A single phrase from the
Precepts Concerning the Decisive Battle issued on 8 April 1945 by Gen Korechika
Anami, Minister of War, will serve to illustrate these measures: all ranks were
exhorted to “possess a deep-seated spirit of ramming”. General Yoshijiro Umezu,
Army Chief of Staff, emphasized that “the certain way to victory… lies in
making everything on Imperial soil contribute to the war effort … combining
the total material and spiritual strength of the nation …” Servicemen and
civilians alike were left in no doubt that the final defence would be to the
death; that all available weapons would be used suicidally.
■ Meeting the Invasion Armada
Imperial General HQ believed (rightly) that an Allied
invasion would be directed first against southern Kyushu and, once a beachhead
was established there, against the Tokyo area, southeast Honshu.
Since the IJN was now almost bereft of surface striking
units, the first line of defence against the invasion armada would be provided
by the remaining aircraft for which pilots and fuel were available – some
10,700 according to USSBS figures – of the Army and Navy. Half of these, 2,700
of the IJN and 2,650 of the IJA, would be kamikaze.
Both the IJN and IJA sought to strengthen the kamikaze units
and to impose some unity of aircraft types within them by producing
purpose-designed suicide planes, of which the IJN’s Yokosuka D4Y4 Model 43 and
Aichi M6A1 are described in Chapter 4. The IJN’s other major attempt at a
“special attack” bomber, intended to be cheaply and quickly manufactured from
non-strategic material, was the wooden-construction Yokosuka D3Y2-K (finally
redesignated D5Y1). The programme was initiated in January 1945 and was aimed
at a production target of 30 per month, but not even a prototype was completed.
The IJA had more success, in terms of production only, with
its Nakajima Ki-115 Tsurugi (“Sabre”). This cheap and simply-produced suicide
bomber was built largely of metal, with a wood-and-fabric tail assembly and,
being intended only for one-way missions, with a jettisonable undercarriage.
The open- cockpit aircraft was theoretically suitable to be flown by a pilot
with only basic training, but not surprisingly in view of the speed of the
development programme (design began on 20 January 1945; the prototype flew only
seven weeks later) it proved a beast to handle, especially during takeoff on
its unsprung undercarriage, which had to be modified. Of the 105 examples
completed by the war’s end, none was operational. No examples were completed of
an improved model, the Nakajima Ki-230, or of the Showa Toka (“Wistaria”), a
copy of the Ki-115 for the IJN.
Kamikaze and conventional air strikes, coordinated with
suicidal attacks by the IJN’s 45 remaining fleet submarines, would begin when
the invasion armada was within c.180 miles (290km) of the Kyushu beaches. As
the armada drew nearer, the rate of attack would increase, with troop
transports the primary targets, until, off the beaches, all remaining aircraft
would be committed to a non-stop mass suicide assault which, it was estimated,
could be sustained for up to 10 days. At this time, the kamikaze would be
supplemented by a “banzai charge” by the IJN’s remaining surface units – only 2
cruisers and 23 destroyers remained fully operational in August 1945 – midget
submarines, human torpedoes and explosive motorboats.
Ambitious building programmes for small “special attack”
craft were severely limited by material and power shortages caused by blockade
and strategic bombing. Thus, by August 1945, there were available in the home
islands only 100 koryu five-man submarines; 300 kairyu two-man submarines; 120
shore-based kaiten human-torpedoes; and about 4,000 shinyo and maru-ni EMBs.
With the exception of the comparatively long-ranging koryu, these small suicide
craft were deployed in well-concealed bases in southern and eastern Kyushu and
southern Shikoku. The major locations were: in Kyushu, Kagoshima (20 kairyu,
500 shinyo), Aburatsu (20 kairyu, 34 kaiten, 125 shinyo), Hososhima (ZO kairyu,
12 kaiten, 325 shinyo) and Saeki (20 kairyu); in Shikoku, Sukumo (12 kairyu, 14
kaiten, 50 shinyo) and Sunosaki (12 kairyu, 24 kaiten, 175 shinyo). The IJA’s
EMBs were similarly but separately dispersed. In addition,
180 kairyu, 36 kaiten and 775 shinyo were deployed around Sagami Wan to defend
the Tokyo area of Honshu. More shinyo and maru-ni (perhaps as many as 1,000 of
each type) remained at bases in Korea, Formosa, Hainan Island, North Borneo,
Hong Kong and Singapore.
■ “Fukuryu”: the Suicide Frogmen
It was estimated that the mass onslaught would destroy some
35–50 per cent of the Allied armada before any troops could be put ashore.
Offshore, a last line of maritime defence would be provided by the least-known
of the “special attack” forces: the demolition frogmen called fukuryu
(“crouching dragons”).
Their training had begun at Kawatana in November 1944 (see
here), although the IJN had employed teams of swimmers on hazardous missions
since early in the war; notably at Hong Kong, where skindivers defuzed Allied mines
to prepare a way for landing craft. A Japanese prisoner taken at Peleliu,
Palaus, late in 1944, claimed that he belonged to a 22-strong Kaiyu unit of
swimmers trained to attack landing craft. Each swimmer was armed with three
grenades, a knife and a simple demolition charge: a wooden box of c.160in3
(2620cm3) packed with trinitrophenol (Lyddite) with a fuze cut to the required
length. But the kaiyu units, credited with damaging an LCI in the Palaus and a
DE and an attack transport at Okinawa, were surface swimmers rather than
frogmen.
The fukuryu appear never to have been deployed outside the
home islands. Their role in the final defence would have been suicidal – as
was, to some extent, their training. Their equipment – a loosely-fitting wet
suit; a clumsy helmet not unlike that of a deep-sea diver; bulky air
circulation and purification tanks strapped to chest and back and linked by a
tangle of hoses – was most unsatisfactory. “There were very many [fatal]
accidents during the training of fukuryu”, a Japanese veteran told me, “because
the twin-tank oxygen re-breathing equipment was no good – but nothing better
was available”. Nevertheless, some 1,200 fukuryu graduated from Kawatana and
Yokosuka Mine School by the war’s end, when 2,800 were still in training.
To destroy inshore landing craft, each fukuryu was armed
with a 22lb (10kg) impact-fuzed charge, incorporating a flotation tank, mounted
on a stout pole (much like the anti-tank “lunge mine” described above). If his
equipment functioned perfectly, the frogman could stay at an optimum depth of
50ft (15m) for up to 10 hours, sustained by a container of liquid food.
Construction was begun of underwater pillboxes, concrete with steel doors, in
which fukuryu would shelter from a pre-landing bombardment while awaiting their
opportunity to sally forth and thrust their explosive lances against the
bottoms of landing craft.
The fukuryu would form part of a network of beach defence.
Farthest from the beach were moored mines, electrically detonated from ashore;
then three lines of fukuryu deployed so that each man guarded an area of
c.470sq yds (390sq m); then lines of magnetic mines; and finally beach mines.
Capt K. Shintani, commanding the fukuryu, was somewhat optimistic in hoping
that his men might “cause as much damage as the kamikaze aircraft”.
■ “Special Motorboats”: Amphibious Tanks
Attacks by fukuryu on landing craft might have been
supported by the few completed Toku 4-Shiki Naikatei (“Type 4 Special Motor
boat”; called the katsu) which, in spite of its designation, was an amphibious
AFV. Originally designed by Mitsubishi for the IJN as a troop, weapon or
freight carrier with a capacity of c.10 tons, the katsu was adapted early in
1944 to serve as a coast defence craft. Only 18 examples of this tracked
amphibian were built.
The katsu’s 240bhp diesel engine gave a maximum land speed
of c.15mph (24kmh) or, driving retractable twin propellers, a water speed of
c.4.5kt (5mph, 9kmh). The craft displaced c.20 tons (20.3 tonnes) and was 36ft
(11m) long overall, 10.8ft (3.3m) in beam, and of 7.5ft (2.3m) draught from
track-base to deck-level. It mounted two 13mm MGs in shielded positions forward
and carried two 17.7in (450mm) torpedoes in launching racks to port and
starboard at deck level. The engine was within a pressurized compartment so
that the katsu might be carried on the casing of a submerged submarine; but a
wild scheme – Tatsumaki-Go (“Operation Tornado”) – to transport katsu in this
way to Bougainville, in mid-1944, for an attack on offshore shipping, was
abandoned, as were plans for their deployment at Peleliu and Saipan. They were
held at Kure for possible employment in the final defence. They were slow,
noisy and unhandy.
■ “Operation Olympic”: the Invasion of Kyushu
Operations “Olympic” (later re-named “Majestic”, but rarely
known thus), the invasion of southern Kyushu scheduled to begin on 1 November
1945, and “Coronet”, the Honshu landings planned for 1 March 1946, would have
been the largest amphibious operations of all time. The US 3rd Fleet (covering
force) and 5th Fleet (amphibious force) would employ more than 3,000 warships
and attack transports, excluding inshore landing boats. Anglo-American naval
strength in the Pacific in August 1945 included approximately 30 fleet
carriers, 78 escort carriers, 29 battleships, more than 50 cruisers and 300
destroyers, and close on 3,000 large landing craft.
Landings on Kyushu would be made by LtGen Walter Krueger’s
6th Army, of three Marine divisions, one armoured division and nine infantry
divisions. And although General Marshall, US Army Chief of Staff, feared that
“Downfall” (ie, both “Olympic” and “Coronet”) would cost at least 250,000 US
casualties, a US War Department study of June 1945 predicted that the initial,
critical, 30-day phase of “Olympic” should involve only c.30–35,000 casualties.
The Japanese hoped to destroy up to 50 per cent of the
invasion force before it hit the beaches. And whatever proportion succeeded in
landing would be opposed à outrance at the water’s edge. Imperial General HQ
reasoned that only if the first of the amphibious assaults was bloodily
repulsed might the Allies be brought to moderate their demand for unconditional
surrender. All Japan’s limited resources must be devoted to this “decisive
battle”, with little or nothing in reserve to counter later landings.
Field-Marshal Hajime Sugiyama, overall commander of the final defence, 1st
General Army HQ, Tokyo, decreed in mid- July: “The key to final victory lies in
destroying the enemy at the water’s edge, while his landings are still in
progress”.
In the summer of 1945, Japan had about 6 million men under
arms, of whom some two-thirds were in isolated island garrisons, in Korea, or
with the Kwantung Army in China-Manchuria, where a Soviet offensive might be
expected. Regular Army forces in the home islands totalled c.2,350,000, with
about 3 million Army and Navy auxiliaries (labour battalions and the like). FM
Shunroku Hata’s 2nd General Army, with its HQ at Hiroshima, was responsible for
Ketsu-Go Area No 6, embracing Kyushu, Shikoku and west Honshu; within this
zone, the vital area of southern Kyushu was covered by the 14 infantry
divisions and two armoured brigades (their AFVs near-immobilized by lack of
fuel) of LtGen Isamu Yokoyama’s 16th Area Army.
Every man of military capability had now been drafted, but
many newly-raised units consisted of ill- trained troops without adequate
armament and sometimes even without full personal kit and uniforms. Transport
was severely limited by a shortage of fuel, vehicles, mechanics, and even
draught animals; communications were disrupted nationwide by the B-29 raids;
and the paucity of adequate construction materials meant that beach defence
works remained incomplete.
■ “One Hundred Million Will Die …!”
As early as 1944, Imperial General HQ had begun constructing
a vast underground complex in the mountainous region of Matsushiro, central
Honshu, with a similar refuge for Emperor Hirohito at nearby Nagano. While the
great ones resisted to the last in this Japanese equivalent of Hitler’s
mythical “Alpine Redoubt”, the ordinary civilians must emulate the aspirations
(but not the almost non-existent exploits) of the German “Werewolf” guerrillas.
In November 1944, on pain of imprisonment in default, all
Japanese male civilians between the ages of 14 and 61 and all unmarried females
of 17–41 were ordered to register for national service as required. From this
register, in June 1945, was drawn the Kokumin Giyu Sento-Tai (“National
Volunteer Combat Force”), of ficially some 28 million strong. Cadres from
Tokyo’s Nakano Gakko (“Army Intelligence School”) were sent throughout Japan –
especially to Kyushu – to instruct this militia in the techniques of beach
defence and guerrilla resistance, as laid down in the People’s Handbook of
Resistance Combat.
Sustained by an individual ration of less than 1,300
calories daily – rice being often bulked out with sawdust or replaced by acorn
flour – the unpaid militia, without uniforms but with armbands denoting
combatant status, drilled with ancient rifles (one to every ten men); swords
and bamboo spears; axes, sickles and other agricultural implements, and even
long-bows, “effective at 50yds (45m)” according to the instruction manual.
Empty bottles were collected to make “Molotov cocktails” and “poison grenades”
filled with hydrocyanic acid; local craftsmen manufactured “lunge mines”,
“satchel charges” and wooden, one- shot, black-powder mortars; and small-arms
workshops, their labour forces decimated by dietary deficiency diseases,
produced single-shot, smooth-bore muskets and crude pistols firing steel rods.
Those who lacked arms of any kind were told to cultivate the
martial arts, judo and karate. Women were advised, with the endorsement of
Empress Nagako, to wear mompei (the loosely-fitting pantaloons traditionally
worn only by peasants working their fields), and were instructed on the
efficacy of a kick to the testicles.
Thus, inspired by the spirit of the Special Attack Corps,
the entire population of Japan stood ready to fight to the death. The slogan
was displayed everywhere: “One Hundred Million Will Die for Emperor and
Nation!”
■ The Last Kamikaze Hits
While most of Japan’s aircraft were reserved for use against
an invasion fleet, a few kamikaze sorties continued to be made against Allied
shipping in the Ryukyus. Most were flown by Shiragiku (“White Chrysanthemum”)
units, so called because they were composed largely of venerable training
aircraft; notably a purpose-modified kamikaze version of the IJN’s Kyushu
K11W1/2 Shiragiku. IJA trainers such as the Kokusai Ki-86 (Allied codename
“Cypress”), and Tachikawa Ki-9 (“Spruce”) and Ki-17 (“Cedar”), all three
biplanes, took part in similar operations.
The last Allied warship sunk by a kamikaze aircraft fell
victim to one of these veterans. From USN reports, which describe the attacker
as a twin-float biplane of wood and fabric construction – and thus immune to
proximity-fuzed shells – the aircraft that fell out of the sky over Okinawa at
0041 on 29 July 1945 to strike USS Callaghan was probably a Yokosuka K5Y2
(“Willow”). This flimsy machine, capable of only 132mph (212kmh) with a maximum
bombload of 132lb (60kg), struck a ready-ammunition locker and triggered a
chain of explosions and fires that sank the big destroyer, with 47 dead and 73
wounded, within 90 minutes. In a similar attack on the following night, another
“sticks-and-string” kamikaze badly damaged USS Cassin Young.
It is generally accepted that the last Allied ship struck by
a kamikaze aircraft was USS Borie (DD 704), damaged by the crash-dive of a lone
“Val” while on radar picket duty for TF 38, as the carriers’ aircraft were
launched off Honshu on 9 August. However, Inoguchi and Nakajima (see
Bibliography) state that the attack transport USS La Grange was damaged by a
kamikaze off Okinawa on 13 August. Also, it is possible that the Russian
minesweeper T-152 (215 tons, 218 tonnes) was sunk by a kamikaze during Soviet
landings on the northern Kuriles on 18–19 August, when a few suicide sorties
are believed to have been flown by IJA aircraft from Shimushu Island.
■ “Body-Crashing”: the Ramming Interceptors
On 14 June 1944, Boeing B-29 Superfortresses struck for the
first time at the Japanese home islands. Most early raids were made at high
level (above c.30,000ft, 9150m), but although Japan’s air defence was deficient
in both AA guns and aircraft with the speed and combat ceiling successfully to
intercept the Superfortresses – of 414 B-29s lost, only 147 fell to Japanese
interceptors or AA fire – it was felt that the results of such operations did
not justify even the lowest loss rate.
Early in 1945, MajGen Curtis LeMay took over the
Marianas-based 21st Bomber Command from BrigGen Haywood Hansell, adopting a
policy of low-level incendiary raids at c.5–6,000ft (1500–1800m) by B-29s
virtually unarmed for extra speed. By August, LeMay could claim that fire raids
had completely shattered some 58 major cities and that by bombing alone Japan
would soon be “beaten back into the dark ages”. Fire raids indeed caused far
greater material and moral damage than the two atomic bombs: on 9–10 March, in
a raid by 325 B-29s, 15.8 sq miles (41 sq km) of Tokyo were gutted and c.84,000
killed and more than 100,000 injured (compared to c.78,000 dead and 68,000
injured in the atomic blast at Hiroshima). In a fire raid on Toyama on 1–2
August, no less than 99.5 per cent of the city was devastated. And when Prince
Konoye told the USSBS that the major factor in Japan’s decision to surrender
was “fundamentally … the prolonged bombing by the B-29s”, he was speaking of
the fire raids. One Japanese statesman, however, referred to the atomic
destruction as “the big kamikaze that saved Japan”; meaning that the terrible
civilian casualties sustained in just these two strikes afforded a decisive
argument to the peace faction.
With fuel stocks low, factories and repair facilities
dislocated, and many aircraft lacking trained pilots or held in reserve for the
final kamikaze onslaught, the Japanese air arms proved unable to deal
effectively with the low-level raiders and thus increasingly resorted to
suicidal aerial ramming interceptions. Isolated instances had occurred earlier
in the war. On 4 July 1942, Lt Mitsuo Suitsu, enraged when his naval air
squadron’s field at Lae, New Guinea, was badly damaged by US bombers, fulfilled
a vow of vengeance by destroying a Martin B-26 Marauder in a head-on collision
with his Zero. The first Army pilot credited with such self-sacrifice was Sgt
Oda who, also flying from New Guinea and unable to maintain the altitude
conventionally to engage a B-17 that was “snooping” a Japanese supply convoy,
brought down the Fortress by ramming with his Nakajima Ki-43 “Oscar”.
Tai-atari (“body-crashing”) tactics were not invariably
fatal: a few US bombers were destroyed by Soviet-style Taran attacks, their
tail assemblies chewed away by fighters with armoured propellers. USAAF
personnel reported the first cases of what they judged to be deliberate ramming
during a raid on the steel works at Yawata, Kyushu, on 20 August 1944. Of four
bombers lost over the target area, one fell to AA, one to aerial gunfire, and
two to a single Kawasaki Ki-45 Toryu (Dragon Killer; “Nick”): the “Nick” rammed
one B-29 and the debris of the two aircraft brought down another.
In February 1945, an IJA manual stated that against B-29s
(and the expected B-32 Dominators, of which only a handful became operational)
“we can demand nothing better than crash tactics, ensuring the destruction of
an enemy aircraft at one fell swoop … striking terror into his heart and
rendering his powerfully armed planes valueless by the sacrifice of one of our
fighters”. The manual noted that only partly trained pilots need be used and
recommended as rammers the Nakajima Ki-44 Shoki (Demon; “Tojo”) and Kawasaki
Ki-61 Hien (Swallow; “Tony”), on the dubious grounds that their designs gave
the pilot a faint chance of baling out immediately before impact.
Earlier than this, in November 1944, the 2nd Air Army’s 47th
Sentai formed the volunteer Shinten Sekutai squadron, dedicated to ramming
attacks in “Tojos”. Their successes included the destruction of a B-29 over
Sasebo on 21 November by Lt Mikihiko Sakamoto; another B-29 on 24 November (one
of only two Superfortresses brought down in a 111-strong raid); and two B-29s
(out of only six lost from a 172-strong force over Tokyo) on 25 February 1945.
Fighters of the Kwantung Army also adopted ramming tactics, bringing down two
B-29s over the Mukden aircraft works on 7 December 1944 and another on 21
December. On both occasions, Japanese aircraft also attempted air-to-air
bombing, releasing time-fuzed phosphorus bombs above the US formations. At
least one B-29 was destroyed by this method, which was also used in the defence
of the homeland.
A less extreme measure than ramming was the formation at
Matsuyama NAFB, Shikoku, in January 1945 of a fighter wing led by Capt Minoru
Genda and including Saburo Sakai and other “aces”. Flying the Kawanishi N1K2-J
Shiden (Violet Lightning: “George”) – probably Japan’s best interceptor; only
c.350 were built – they achieved especially good results against Allied carrier
strikes. On 16 February, WO Kinsuke Muto was credited with engaging
single-handed 12 F6F Hellcats from USS Bennington over Atsugi, Tokyo, shooting
down four and driving off the rest.
■ Attempted Aid from Germany
Unable to produce in sufficient quantity such advanced
interceptors as the Kawasaki Ki-100 (396 of all models built), the Kawasaki
Ki-102 (“Randy”; 238 built) and the Mitsubishi A7M3-J Reppu (Hurricane; “Sam”;
prototype only), or to bring to operational status the Funryu (“Raging Dragon”)
surface-to-air guided missiles, Japan sought German aid. Plans, and in some
cases completed models, were acquired of the Bachem Natter, the Reichenberg
piloted-bomb (built as the Baika), and the Messerschmitt Me 262 twin-engined
jet fighter-bomber. A prototype based on the latter, the IJN’s Nakajima Kikka
(“Orange Blossom”), flew on 7 August 1945; if production had been attained it
was to have been deployed in concealed revetements as a “special attack”
bomber.
A major effort at a point-defence interceptor was the joint
IJN/IJA project for the Mitsubishi J8M1 (Navy) or Ki-200/202 (Army) Shusui
(“Swinging Sword”), a near-identical version of the Luftwaffe’s Messerschmitt
Me 163 Komet. Rights to produce a version of the Komet’s airframe and Walter
HWK 509A bi-propellant (T-Stoff and C-Stoff, which the Japanese called Ko and
Otsu liquids respectively) rocket engine, with a completed example of the
aircraft itself, were purchased as early as March 1944; but only one Walter
unit and an incomplete set of blueprints reached Japan. Germany’s final effort
to provide her ally with more material on the Komet and other “special weapons”
was made on 2 May 1945, when U.234 (Cdr Johann Fehler) sailed from Norway for
Japan with high-ranking Luftwaffe officers, technicians, and two Japanese
scientists aboard. En route, Fehler received the news of Germany’s collapse
and, as he headed for the USA to surrender his boat, both Japanese committed
seppuku.
In Japan, training with the Komet-replica MXY8 Akigusa
(“Autumn Grass”) glider began in December 1944. The first powered flight was
attempted on 7 July 1945 at Yokoku airfield, Yokosuka. Successfully jettisoning
the takeoff trolley, LtCdr Toyohiko Inuzuka had reached c.1,300ft (400m) when,
probably because of a fuel line blockage caused by the steep climb, the engine
flamed out and the Shusui stalled and crashed, mortally injuring Inuzuka. Later
that month, an explosion of the volatile fuel mixture during ground testing
killed another of the project’s officers. Many similar fatalities – especially
during the hard skid-landings that often brought the liquid propellants
violently together – had occurred in Germany, where the “Devil’s Egg” was
regarded by many Luftwaffe personnel as semi-suicidal at best.
The Japanese rocket interceptor differed little from its German pattern. The J8M1 had a span of 31.2ft (9.5m), a length of 19.86ft (6.05m) and a height on its jettisonable trolley of 8.86ft (2.7m). Powered by a Toko Ro.2 motor giving 3,307lb (1500kg) thrust for up to c.5.3 minutes, it was estimated to be capable of a maximum 559mph (900kmh) at 32,810ft (10,000m); thus probably having a range at optimum flight profile of less than 60 miles (96km). Its armament was to be two wing-mounted 30mm cannon – although if the planned production of more than 1,000 examples by August 1945 had been achieved, it is likely that many would have been expended in ramming attacks after exhausting their ammunition of 50 rounds per gun. In the event, only seven Shusui, which were to have been operated by the 312th Naval Air Group, were completed by the war’s end.
