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| This aerial view shows Japan’s home fleet, arrayed in battle line, on October 29, 1940, off the coast of Yokohama, Japan. |
During World War II, at the
beginning of the Pacific War in December 1941, the Imperial Japanese Navy (IJN)
was the third most powerful navy in the world, and Japan's naval air service
was one of the most potent air forces in the world. During the first six months
of the war, the IJN enjoyed spectacular success, inflicting heavy defeats on
Allied forces while remaining undefeated in battle. The attack on Pearl Harbor
crippled the battleship arm of the US Pacific Fleet, while Allied navies were
devastated during Japan's conquest of Southeast Asia. Land-based IJN aircraft
were also responsible for the sinkings of HMS Prince of Wales and HMS Repulse,
the first time in history that capital ships were sunk by aerial attack while
underway. In April 1942, the Indian Ocean raid drove the Royal Navy from South
East Asia. After these successes, the Japanese concentrated on the elimination
and neutralization of strategic points from which the Allies could launch
counteroffensives against Japan's conquests. However, at Coral Sea the Japanese
were forced to abandon their attempts to isolate Australia, while the defeat at
Midway forced them onto the defensive. The campaign in the Solomon Islands,
during which the Japanese lost a months-long battle of attrition, was a
decisive defeat for the IJN; they had failed to commit sufficient forces in time
to overcome the growing Allied strength in the Solomons.
During 1943 the Allies were
able to significantly reorganize and expand their forces, and American
industrial strength began to turn the tide of the war. The United States
ultimately managed to gain the upper hand through a vastly greater industrial
output and a modernization of its air and naval forces, while the Japanese
wartime economy and military-technological innovation stagnated. In 1943, the
Japanese turned their attention to maintaining a defensive perimeter around
their previous conquests. Land-based troops and aircraft on Japanese-held
islands in Micronesia were tasked with absorbing and wear down an expected
American counteroffensive. However, American industrial power proved impossible
for the Japanese to overcome; the Allied military forces that faced the
Japanese in 1943 were so overwhelming in firepower and equipment that from the
end of 1943 to 1944 Japan's defensive perimeter began to buckle, and finally
collapsed. In June 1944, Japanese naval airpower was effectively annihilated
during at the Philippine Sea, with American pilots terming it the "Great
Marianas Turkey Shoot," while the battle of Leyte Gulf in October 1944
destroyed a large part of the IJN's surface fleet. Consequently, the Japanese
lost control of the Western Pacific and access to the oil fields of Southeast
Asia, upon which the IJN was reliant for continued operations at sea. During
the final phase of the war, the Japanese resorted to a series of desperate
measures, including a variety of suicidal attacks popularly known as kamikaze.
By May 1945, most of the Imperial Japanese Navy had been sunk, and the remnants
had taken refuge in harbors on the Japanese Home Islands. By July 1945, all but
one of the IJN's capital ships had been sunk in raids by the United States
Navy. By the end of the war, the IJN had lost 334 warships and 300,386 officers
and men.
Strategy
At the beginning of the Pacific
War, the strategy of the Imperial Japanese Navy was underpinned by several key
assumptions. The most fundamental was that just as the Russo-Japanese War had
been decided by a single naval battle at Tsushima (May 27–28, 1905), the war
against the United States would also be decided by a single, decisive battle at
sea, or Kantai Kessen. Japanese planners believed that this great maritime
clash would be determined by battleships armed with large-caliber guns, a
conviction shared by American naval leaders as well. All other arms of the navy
were to be utilized in a subordinate role, supporting IJN the battleships when
they eventually met the Americans in battle. The Japanese assumed that at the
start of any conflict they would quickly seize the largely unprotected
American-held Philippines. This would force the United States to undertake a
drive across the Pacific to retake them. Consequently, the Japanese planned for
a decisive naval clash that would take place somewhere in the western Pacific,
the region that the Japanese decided was optimal for the IJN to stop an
American advance.
It was also clear to the
Japanese that in order to win a decisive battle over the United States Navy,
they would have to make up for a significant numerical disadvantage in both
ships and planes. The Japanese acknowledged that they would never have the
industrial capacity to create a navy that was equal in size to the United
States. However, as they were planning on fighting a defensive war, they
calculated that they only required 70 percent of the strength of the United
States Navy to be in a position to achieve victory. This assumption was
premised upon two expectations, both of which became driving forces in Japanese
naval construction, tactical development and training during the interwar period.
The first was that the Japanese would have to employ the proper weapons and
tactics to inflict severe attrition on the US Pacific Fleet before it could
engage the main surface elements of the Combined Fleet, which the Japanese
believed would bring their naval forces to at least parity with the Americans.
Once rough force parity had been achieved, Japanese naval units utilizing
superior speed, gunnery range and training would win the day.
Yamamoto's
Revised Plan
The naval war that Japan fought
in the Pacific during 1941-45 reflected a very different strategy from the one
the IJN had been planning and training for throughout the interwar period. This
was due to the views and actions of Admiral Isoroku Yamamoto, who had assumed
command of the Combined Fleet in August 1939. Virtually overnight, Yamamoto
altered the passive wartime strategy of seizing the Philippines and awaiting an
American naval advance into the western Pacific to a much more aggressive,
forward-facing strategy. Yamamoto had first discussed an attack on Pearl Harbor
in March or April 1940. After the completion of the Combined Fleet's annual
maneuvers in the fall of 1940, Yamamoto ordered a study on the feasibility of
an attack on Pearl Harbor to be performed under utmost secrecy. By December
1940, Yamamoto had decided that any war against the United States should begin
with an attack on Pearl Harbor. He believed that since a traditional naval
victory against the United States was not possible, he had to shatter American
morale and force a negotiated peace. For this reason, he scrapped the passive
strategy of creating conditions for a decisive battle in the western Pacific in
favor of a preliminary strike so crippling that it would undermine the American
will to fight a lengthy war.
The operation was risky as it
exposed the IJN's most powerful striking force to early destruction.
Consequently, Yamamoto had great difficulty getting his plan to attack Pearl
Harbor approved by a skeptical Naval General Staff. In a series of meetings on
October 17–18, 1941, Yamamoto threatened to resign unless his plan was
approved. This threat finally brought approval of his plan as Yamamoto was
viewed as too valuable to lose. What made the whole operation possible was the
formidable Kido Butai with six carriers and over 400 embarked aircraft.
The Japanese strategy for the
coming conflict would be to fight a limited war, in which Japan would seize key
objectives and then create a defensive perimeter to defeat Allied
counterattacks. This would in turn lead to a negotiated peace settlement. The
initial period of the war was divided into two operational phases. The First
Operational Phase was further divided into three separate parts; during these,
the major objectives of the Philippines, British Malaya, Borneo, Burma, Rabaul,
and the Dutch East Indies would be occupied. The Second Operational Phase would
entail further expansion into the South Pacific by seizing eastern New Guinea,
New Britain, the Fiji Islands, Samoa, and strategic points in the Australian
area. In the Central Pacific, Midway would be taken as well as the Aleutian
Islands in the Northern Pacific. Seizure of these key areas would provide a
defensive perimeter and depth to deny the Allies staging areas from which to
mount a counteroffensive.
Naval Operations (1941–1942)
Pearl
Harbor
On December 7, 1941, two waves
of 350 aircraft from the six carriers of the Kido Butai gained complete
surprise and successfully hit their intended targets. The initial attacks against
Hawaiian airfields were also very successful and negated any possibility of an
effective airborne defense, or the initiation of a retaliatory strike on the
Japanese carriers by American aircraft. Forty B5N torpedo bombers were the most
crucial part of the operation since they were to be targeted against the main
battleships and carriers. Of the eight American battleships present in the
harbor, five were subjected to torpedo attack and Japanese torpedo aircraft
were responsible for the sinking of the battleships Oklahoma, West Virginia and
California. A single torpedo hit also struck the Nevada. Additionally,
torpedoes sank a target ship and a minelayer, and damaged the two light
cruisers, Helena and Raleigh. In return, the Japanese only lost five torpedo
bombers.
The efforts of the torpedo
bombers were complemented by an additional 49 B5N configured as level bombers
and armed with 1,760lb armor-piercing bombs. They dropped their payload from
10,000 feet (3,000 m), scoring ten hits. One of these penetrated the forward
magazine of battleship Arizona and completely destroyed the ship. Other hits
slightly damaged the battleships Maryland, West Virginia, and Tennessee. The
167 aircraft of the second wave, however, accomplished much less. This attack
wave included 78 dive-bombers with the IJN's best crews. However, against
stationary targets, they scored only some 15 hits including five on the Nevada,
which slowly moved down the channel to the harbor entrance. Nevada was
subsequently beached to avoid blocking the channel. A single bomb hit struck
the battleship Pennsylvania, which was in dry dock, but caused only light
damage. The light cruiser Honolulu also suffered a near miss that caused
moderate damage.
American losses were heavy;
2,403 personnel and bystanders were killed, 18 ships were damaged or sunk, and
188 aircraft were destroyed. In contrast, the Japanese lost 29 aircraft and
five midget submarines. The Japanese judged the attack as a success, believing
that they accomplished their primary tactical goal, which was the destruction
of the battle line of the U.S. Pacific Fleet. The Japanese operations to
conquer Southeast Asia and establish to a defensive perimeter could proceed
without interference, and the U.S. Navy was unable to launch a major
trans-Pacific counteroffensive for two years. However, the two American
carriers were at sea at the time of the attack and Pearl Harbor's oil storage,
dry dock, submarine piers and maintenance facilities were left unscathed.
Additionally, contrary to the planned shattering of American morale, forcing
the U.S. government to seek a compromise peace with Japan, the enormous loss of
life and property from the sneak attack led to a tidal wave of outrage by the
American public.
First
Operational Phase
To the surprise of the
Japanese, the First Operational Phase went according to plan with extremely
light losses. No ship larger than a destroyer was sunk. The invasion of Malaya
and the Philippines began in December 1941. The island of Guam was seized on
December 8 after token American resistance. The British Gilbert Islands were
seized on December 9 and 10. Japanese Land based naval bombers achieved notable
success on December 10, when operating from bases in Indochina, they sank the
British capital ships Prince of Wales and Repulse. The only temporary setback
for the Japanese was the failure of the first attempt to seize Wake Island on
December 11. In response, a carrier division from the Pearl Harbor attack force
was diverted to Wake Island for a second attempt on December 22, which was
successful. The British naval base of Singapore also surrendered on February
15.
Allied naval opposition to the
IJN during the First Operational Phase was sporadic and ineffective. In the
first major surface engagement of the war on February 27 at the Java Sea, an
Allied naval force was defeated by a Japanese one of similar size. Following
its debut at Pearl Harbor, the Kido Butai supported the capture of Rabaul in
January 1942 and the Dutch East Indies in February. The only problem
encountered by the Japanese during the First Operational Phase was the failure
to occupy the Philippines on schedule. However, with no expectation of
reinforcement, the fall of the Philippines was only a matter of time and the
remaining American and Filipino forces surrendered in early May 1942.
Indian
Ocean Raid
The last major operation of the
First Operational Phase was the Combined Fleet's raid into the Indian Ocean,
code-named Operation C. It was essential for the completion of the defensive
perimeter.
This significant operation
included five carriers to neutralize the Royal Navy's Eastern Fleet with an
attack on Ceylon, the heart of British naval power in the East, and a task
force built around heavy cruisers to attack shipping in the Bay of Bengal. The
operation began in April with the Japanese delivering heavy attacks against
British bases at Colombo and Trincomalee. Japanese carrier aircraft also caught
and sank a light carrier HMS Hermes and the two heavy cruisers HMS Dorsetshire
and HMS Cornwall, but were unable to locate and destroy the main British fleet.
The Japanese cruiser raiding force wreaked havoc with British shipping in the
Bay of Bengal. From April 4 to 9, the Japanese sank 23 merchant ships totaling
32,404 tons. However, the entire operation was a strategic dead end since it
was only a temporary projection of power that could not be sustained and served
only to put more strain on the Japanese carrier force.
Strategic Setbacks (1942)
The ease with which the
Japanese accomplished their initial objectives led to the severe
underestimation of the enemy and the resultant failure to concentrate the IJN's
superior forces at key places and times. As a result, the critical months of
May and June 1942 saw the IJN lose both its offensive power and the initiative.
The Second Operational Phase was planned to expand Japan's strategic depth by
adding eastern New Guinea, New Britain, the Aleutians, Midway, the Fiji
Islands, Samoa, and strategic points in the Australian area. However, the Naval
General Staff, the Combined Fleet, and the Imperial Army, all had different views
on the next sequence of operations. The Naval General Staff advocated an
advance to the south to seize parts of Australia, however, the Imperial
Japanese Army declined to contribute the forces necessary for such an
operation, which quickly led to the abandonment of the concept. The Naval
General Staff still wanted to cut the sea links between Australia and the
United States by capturing New Caledonia, Fiji, and Samoa. Since this required
far fewer troops, on March 13 the Naval General Staff and the Army agreed to
operations with the goal of capturing Fiji and Samoa. The Second Operational
Phase began well when Lae and Salamaua located on eastern New Guinea were
captured on March 8. However, on March 10, American carrier aircraft attacked
the invasion forces and inflicted considerable losses. The raid had major
operational implications since it forced the Japanese to stop their advance in
the South Pacific. This was to be the last of the uninterrupted victories for
the Japanese until the Combined Fleet provided the means to protect future
operations from American carrier attack.
In April 1942, the Doolittle
Raid, carried out by 16 bombers that took off from the aircraft carrier USS
Hornet, 600 miles (970 km) from Japan, also had a major impact on Japanese
strategy. The raid inflicted minimal material damage on Japanese soil but had
major psychological repercussions in exposing the vulnerabilities of the
Japanese homeland. Consequently, as the raid was mounted by a carrier task
force, it highlighted the dangers the Japanese home islands would face until
the destruction of the American carrier forces could be achieved. With only
Marcus Island and a line of converted trawlers patrolling the vast waters that
separate Wake and Kamchatka, the Japanese east coast was left open to attack.
Coral
Sea
Yamamoto thought it essential
to complete the destruction of the United States Navy that had begun at Pearl
Harbor. His proposal to achieve this was by attacking Midway Atoll, an
objective he believed the Americans would have no choice but to fight for. Due
to its proximity to Hawaii, they would be forced to contest a Japanese invasion
there. During a series of meetings held from April 2–5 between the Naval
General Staff and representatives of the Combined Fleet, a compromise was
reached. Yamamoto got his Midway operation, but only after he had threatened to
resign once more. In return, however, Yamamoto had to agree to two demands from
the Naval General Staff both of which had implications for the Midway
operation. In order to cover the offensive in the South Pacific, Yamamoto
agreed to allocate one carrier division to the operation against Port Moresby.
Yamamoto also agreed to include an attack to seize strategic points in the
Aleutian Islands simultaneously with the Midway operation. These were enough to
remove the Japanese margin of superiority in the coming Midway attack.
The attack on Port Moresby was
codenamed the MO Operation and was divided into several parts or phases. In the
first, Tulagi would be occupied on May 3. The carriers would then conduct a
wide sweep through the Coral Sea to find and attack and destroy Allied naval
forces, with the landings conducted to capture Port Moresby scheduled for May
10. The MO Operation featured a force of 60 ships led by the two carriers:
Shōkaku and Zuikaku, one light carrier (Shōhō), six heavy cruisers, three light
cruisers, and 15 destroyers. Additionally, some 250 aircraft were assigned to
the operation including 140 aboard the three carriers. However, the actual
battle did not go according to plan, although Tulagi was seized on May 3. The
following day, aircraft from the American carrier Yorktown struck the invasion
force. For the next two days, both the American and Japanese carrier forces
tried unsuccessfully to locate each other. On May 7, the Japanese carriers
launched a full strike on a contact reported to be enemy carriers, but this
report turned out to be false. The strike force found and struck only an oiler,
the Neosho and the destroyer Sims. The American carriers also launched a strike
on incomplete reconnaissance. Instead of finding the main Japanese carrier
force, they only located and sank the Shōhō. On May 8, the opposing carrier
forces finally found each other and exchanged strikes. The 69 aircraft from the
two Japanese carriers succeeded in sinking Lexington and damaging Yorktown. In
return the Americans damaged Shōkaku. Although Zuikaku was left undamaged,
aircraft losses to Zūikakū were heavy and the Japanese were unable to support a
landing at Port Moresby. As a result, the MO Operation was cancelled. Although
they managed to sink a carrier, the battle was a disaster for the IJN. Not only
was the attack on Port Moresby halted, which constituted the first strategic
Japanese setback of the war, all three carriers that were committed to the
battle would now be unavailable for the operation against Midway.
Midway
Yamamoto perceived Operation
MI, the capture of Midway, as the potentially decisive battle of the war which
could open the door for a negotiated peace favorable to Japan. For the
operation, the Japanese had only four carriers; Akagi, Kaga, Sōryū and Hiryū.
Through strategic and tactical surprise, the carriers would knock out Midway's
air strength and soften it for a landing by 5,000 troops. After the quick
capture of the island, the Combined Fleet would lay the basis for the most
important part of the operation: Midway was to be bait for the USN which would,
in Japanese calculations, depart Pearl Harbor to counterattack after Midway had
been captured. When the US Pacific Fleet arrived, Yamamoto would concentrate
his scattered forces to defeat the Americans. Concurrently with the attack on
Midway, an important aspect of the scheme was Operation AL, the plan to seize
two islands in the Aleutians to deny American forces the use of bases close to
Japan. Contradictory to persistent myth, Operation AL was not a diversion to
draw American forces from Midway: the Japanese wanted the Americans to be drawn
to Midway, rather than away from it. However, American codebreakers had deduced
an attack on Midway was imminent and American forces, including three carriers
were deployed from Pearl Harbor to the Midway area, unknown to the Japanese.
The battle began on June 3,
when American aircraft from Midway spotted and attacked the Japanese transport
group 700 miles (1,100 km) west of the atoll. On June 4, the Japanese launched
a 108-aircraft strike on the island, the attackers brushing aside Midway's
defending fighters but failing to deliver a decisive blow to the island's
facilities. Most importantly, the strike aircraft based on Midway had already
departed to attack the Japanese carriers, which had been spotted. This
information was passed to the three American carriers and a total of 116
carrier aircraft, in addition to those from Midway, were on their way to attack
the Japanese. The aircraft from Midway attacked, but failed to score a single
hit on the Japanese fleet. In the middle of these uncoordinated attacks, a
Japanese scout aircraft reported the presence of an American task force, but it
was not until later that the presence of an American carrier was confirmed.
Vice Admiral Chuichi Nagumo, was put in a difficult tactical situation in which
he had to counter continuous American air attacks and prepare to recover his
Midway strike, while deciding whether to mount an immediate strike on the American
carrier or wait to prepare a proper attack. After quick deliberation, he opted
for a delayed but better-prepared attack on the American task force after
recovering his Midway strike and properly arming aircraft. However, beginning
at 10:22am, American carrier dive-bombers surprised and successfully attacked
three of the Japanese carriers. With their hangar decks full of fueled and
armed aircraft, plus discarded bombs and torpedoes, all three carriers were
turned into blazing wrecks. Only a single carrier, Hiryū, remained operational
and she launched an immediate counterattack. Both of her attacks damaged
Yorktown and put the US carrier out of action. Yorktown, along with the
destroyer Hammann, were later sunk by the Japanese submarine I-168. Later in
the afternoon, aircraft from the two remaining American carriers found and
destroyed Hiryū. With the striking power of the Kido Butai having been
destroyed, Japan's offensive power was blunted. Subsequently, on the early
morning of June 5, the Japanese cancelled the Midway operation and the
strategic initiative in the Pacific was in the balance.
Impact
of Midway
Although the Japanese had lost
four fleet carriers, the worst consequences of Midway were the loss of
experienced aircraft maintenance personnel.* Mark Peattie states that the
engagement was "not the battle that doomed Japan". The outcome did
not lead to the end of the highly trained carrier aircrews or radically degrade
the fighting capabilities of Japanese naval aviation as a whole. The Japanese
only lost 110 aircrew during the battle, mostly from Hiryū with American
aircrew losses being far greater than the Japanese. The Japanese still had more
warships of every category than the United States had in the Pacific and the
Combined Fleet still possessed eight aircraft carriers, twice as many as the US
Pacific Fleet. Additionally, while the United States did have three large
carriers in the Pacific, in comparison to Japan's two, the Japanese vessels had
a total capacity for 382 aircraft, compared to 300 on the American carriers.
The IJN had another carrier already fitting out to join the fleet and two more
in the later stages of construction. American industry would deliver only small
escort carriers during 1942, of which more than two thirds were sent to the
Atlantic; the massive shipbuilding program would not get into full gear until
the following year. Consequently, for the time being the Japanese retained the
advantage. As for naval aircraft, the Japanese were as strong as they had been
at the beginning of the war. Until May and June 1942, air losses had been
limited and aircraft production had kept pace with losses. From the beginning
of war through the end of June, Japanese naval aircraft losses totaled 1,641.
Almost half of the losses occurred during the months when the battles of Coral
Sea and Midway took place, with the large majority in June, including many at
Midway. Over the same period Japanese aircraft deliveries numbered 1,620.**
Additionally the loss of pilots was not yet of major concern, as aircrew
casualties at Midway were not so severe and the large majority of aircrew of
the Kido Butai returned despite the sinking of their ships. These were
bolstered by 2,000 newly trained pilots in 1942.***
* Skilled ground crew and
aircraft maintenance personnel may have accounted for twenty six hundred of the
three thousand personnel who went down with the four carriers. The loss of 40%
of the four carriers' highly trained aircraft mechanics and technicians,
including the essential flight-deck crews etc., together with the loss of
organizational knowledge exemplified in such highly trained crews, were a blow
to the IJN.
** Prados notes the most
significant shortfall was in single-engine attack aircraft (dive bombers and
torpedo planes) where 374 were lost against the induction of 240 new planes.
Commander Okumiya Masatake, an air staff officer and experienced pilot, also
recorded that at mid-July 1942 the order of battle for Japanese naval aviation
was slightly stronger in fighters than before the war, though it had declined
by roughly a quarter in attack aircraft. Land-based medium-bomber strength was
actually greater than it had been at the start of the war.
*** During Midway more than a
hundred aircrew and pilots were killed, with the bulk lost concentrated among
the carrier attack squadrons. The IJNAS had begun the war with nearly 2,000
pilots, almost all of them highly skilled and about half being carrier
qualified. Most of the initial cadre had more than 600 hours of flying
experience, many of them expert pilots with thousands of hours in the air
including combat experience in China. In comparison, a typical USAAF pilot in
the autumn of 1942 went to the front line with 300 flight hours. The IJN would train
about 2,000 new pilots in 1942. That summer, when the campaign in the Solomons
began, an estimated over 85 percent of naval pilots still met the expert
standard of more than 600 flying hours.
Guadalcanal and the Solomons (1942–1943)
On August 7, 1942, U.S. Marines
landed on the islands of Guadalcanal and Tulagi in the Solomons, putting the
Japanese on the strategic defensive for the first time in the war. Vice Admiral
Gunichi Mikawa, commander of the newly formed Eighth Fleet at Rabaul, reacted
swiftly. Gathering five heavy cruisers, two light cruisers, and a destroyer, he
sailed south and attacked the Allied naval force off the coast on the night of
August 8–9. Mikawa's quick response resulted in the Battle of Savo Island, in
which four Allied heavy cruisers were sunk with no Japanese ships lost. This
was the worst defeat ever suffered by the U.S. Navy while at sea, only
mitigated by the failure of the Japanese to attack the vulnerable American
transports.
Aside from Mikawa's initial reaction,
the Japanese were slow to respond, seeing the American landings as a
reconnaissance-in-force, but by mid-August they had assembled four battleships,
five carriers, 16 cruisers, and 30 destroyers to dislodge the Americans. On
August 24–25, the IJN launched an operation intended to send a small transport
convoy to the island and also to destroy any American naval vessels in the
area. The ensuing Battle of the Eastern Solomons was the third carrier battle
of the war. The IJN achieved neither of their goals, with the convoy diverted
to the Shortland Islands and the American navy still present. Japanese losses
were heavy, with 75 carrier aircraft, a light carrier, a transport, and a
destroyer lost. Although the American carrier Enterprise was damaged, she
managed to elude Japanese attempts to sink her. With the Americans' Henderson
Field on Guadalcanal now operational, convoys of slow transports could not go
near the island without great risk. Consequently, until the airfield was
suppressed, Japanese reinforcements were most-often delivered by inefficient
destroyer runs to the island by night.
By early September, destroyers
had delivered 6,200 troops for an attack on the American perimeter, but the
Japanese had underestimated American forces on the island, assuming there were
only 2,000 Marines: the actual number was about 20,000. The attacks launched by
the Japanese on the nights of September 12–14 therefore failed. The Japanese
did better in the struggle for control of the waters around Guadalcanal. On
September 15, the submarine I-19 sank the carrier Wasp, leaving only a single
American carrier, the Hornet, active in the Pacific. But although the Japanese
possessed up to six operational carriers during the same period, they failed to
capitalize on the opportunity.
By now the Japanese realized
that Guadalcanal was a pivotal contest, so for the next offensive an entire
Army division was assigned, with plans to get it to Guadalcanal by mid-October
for an offensive beginning October 20. To support this effort, the Combined
Fleet stepped up night runs by destroyers and high-speed seaplane carriers
(which carried the soldiers' heavy equipment) to Guadalcanal, and a transport
convoy was assembled. Aerial bombardment of Henderson Field would be
intensified, and surface warships would bombard the airfield. Admiral Yamamoto
now defined the Combined Fleet's primary mission as supporting the recapture of
the island, with destruction of the US Pacific Fleet a secondary objective. On
the night of October 13–14, the battleships Kongō and Haruna bombarded the
airfield on Guadalcanal with 918 14-inch (36 cm) rounds, destroying over 40
aircraft and putting the airfield temporarily out of commission. (Mark Stille
notes that despite Japan's prewar preoccupation with a titanic clash of
battleships, this was the most successful Japanese battleship operation of the
war.) The convoy arrived during the night of October 14–15, preceded by two
heavy cruisers which shelled the airfield. Aircraft from two carriers flew
cover over the transports. American aircraft succeeded in sinking three of the
six transports, but not before a total of 4,500 men had landed along with
two-thirds of their supplies and equipment. The Japanese kept up the pressure with
another cruiser bombardment on the night of October 15–16 and more
reinforcement destroyer runs. After several delays, the Japanese began the
offensive on October 24. The main attack finally commenced on the night of
October 25–26, but the attacks on Henderson field were repulsed by the Marines
with heavy losses.
Santa
Cruz
Concurrently with the Army's
offensive on Guadalcanal, the IJN planned their largest naval operation to date
in order to counter and defeat any American naval forces operating in support
of the Marines on Guadalcanal. The Combined Fleet departed Truk on October 11
with a force of four battleships, four carriers, nine cruisers, and 25
destroyers. In addition, the Eighth Fleet in Rabual contributed four more
cruisers and 16 destroyers. On October 25, Yamamoto ordered the Combined Fleet
to engage the Americans. Just after midnight on the night of 25–26 October, an
American PBY patrol aircraft located the Japanese fleet. Finding the Japanese
force just before dawn, two SBDs dive-bombers from the Enterprise attacked
Zuihō and scored a pair of hits that damaged the flight deck, starting numerous
fires on board the carrier. However, the Japanese had already launched a
sixty-five aircraft strike against the American task force. Through a ring of
antiaircraft fire and the carriers fighter cover, the Japanese dive and torpedo
bombers registered a number of hits on Hornet. By 9.30 am Hornet was dead in
the water, but planes from the Hornet had also located the Japanese. Six
American bombs struck the deck of Shōkaku, removing her from the battle. Some
Hornet SBSs attacked the heavy cruiser Chikuma, damaging her so severely that
she was forced to return to the port at Truk. The Battle of Santa Cruz was the
fourth carrier clash of the war. The Japanese managed to sink the carrier
Hornet , damaged Enterprise, a battleship, a cruiser, and a destroyer. Yamamoto
ordered his subordinates to seek a night battle to finish off the fleeing
Americans, but their fuel situation forced them to return to Truk by October
30. Although American losses had been high, the Japanese had been turned back.
Two Japanese carriers were heavily damaged and carrier air groups had also been
decimated with the greatest single loss of carrier aircrews to date, 148 aviators.
These losses prevented the Japanese from exploiting their success.
Failure
to Take Guadalcanal
The battle for Guadalcanal
reached a crescendo in November. After the victory at Santa Cruz, the Japanese
were sure that the naval balance in the south Pacific had swung in their favor.
They planned a more substantial effort to reinforce the island. A similar plan
to the one conducted in October was put forward, with a larger convoy preceded
by another bombardment by battleships to neutralize the airfield. The Japanese
were prepared to employ sufficient forces to guarantee its success. On the
night of November 12–13, a force of two battleships, Hiei and Kirishima, one
light cruiser and 11 destroyers departed for Guadalcanal to bombard the
airfield. However, this attempt was thwarted by a smaller American force of
five cruisers and eight destroyers, which intercepted the Japanese force. A
vicious night action ensued at close range. Losses were heavy on both sides,
but the critical bombardment of the airfield never occurred. Hiei was damaged
and the following day was sunk by American aircraft, becoming the first
Japanese battleship to be lost in the war. The Japanese then attempted another
bombardment with a force centering on the battleship Kirishima, with support
from two heavy cruisers and two destroyer squadrons. The IJN had additional
battleships that were available, but were not employed. On the night of
November 14–15, this attempt was again met by the American force which included
two battleships, Washington and South Dakota. In another vicious night battle,
the Japanese were again turned back, losing the battleship Kirishima during the
first battleship duel of the Pacific War. These two night battles became known
as the First and Second Naval Battles of Guadalcanal. They were the decisive
events of the campaign. While the Americans had delivered large numbers of
additional troops to Guadalcanal, the Japanese only delivered 2,000 troops and
an insignificant amount of supplies. Additionally, the large Japanese convoy
had lost all ten transports, which had been sunk by American aircraft from the
undamaged airfield. Naval losses were heavy for both sides; the Americans lost
two cruisers and seven destroyers and many ships had been severely damaged. The
Japanese lost two battleships, a heavy cruiser, and three destroyers. The Japanese
had been defeated more by a failure to mass their forces rather than by being
outfought. The attrition suffered by the Japanese during the battles for
Guadalcanal was too great. On January 4, the Navy Section of the Imperial
General Headquarters instructed Yamamoto to prepare the withdrawal of the
remaining troops from Guadalcanal. The evacuation of Guadalcanal was codenamed
Operation Ke. The Americans detected the preparations for the operation and
believed they were actually for another Japanese attempt to reinforce the
island. The evacuation was carefully planned to take place in three destroyer
lifts and would begin in late January 1943. The first operation was conducted
with 20 destroyers on February 1, another with 20 destroyers was conducted on
February 4. A third and final operation was conducted with 18 destroyers on
February 7. Operation Ke was successful and 10,652 men, were evacuated from
Guadalcanal, with Japanese losses only being a single destroyer.
Central
Solomons and New Guinea
With Guadalcanal lost, the
Japanese focus shifted to the Central Solomons and New Guinea. However, during
the Battle of the Bismarck Sea on March 2–4, an Allied air attack destroyed a
convoy attempting to move troops from Rabaul to Lae on New Guinea. To rectify
Japan's declining position, Yamamoto devised a major air offensive to counter
the growing Allied strength in the Solomons. He moved the air groups of the
Combined Fleet's four carriers of about 160 aircraft, to Rabaul to join the 190
aircraft of the Eleventh Air Fleet. This brought the Japanese air strength
there to some 350 aircraft. The air offensive was codenamed Operation I-Go,
consisting of four major attacks conducted on Allied positions on Guadalcanal,
Buna, Port Moresby and Milne Bay on April 7, 11, 12 and 14, respectively. In
mid-April, the IJN concluded the operation, claiming success against Allied
shipping and defending fighters. In fact, little had been achieved and Japanese
losses were heavier than those suffered by the Allies, resulting in further
attrition to the vital Japanese carrier aircrews. During 1943, the IJN
attempted to preserve its strength in the face of two attack routes by the
Americans. In the Solomons, the action turned to the Central and Northern
Solomons between March and November. During this period, the Japanese and
Americans fought seven surface engagements. All of these actions were fought at
night during which the Japanese still enjoyed an advantage. Twice, Japanese
destroyers defeated an Allied force composed of cruisers and destroyers,
demonstrating the Japanese prowess at night fighting.
In early August, at Vella Gulf,
three out of four Japanese destroyers were sunk by American destroyers using
radar with a new doctrine that emphasized torpedo attacks. It was the first
time in the war that Japanese destroyers had been beaten during a night battle.
The next action, fought on August 18, was indecisive. On October 6, the two
sides met again. Japanese torpedoes shattered the American formation, but the
Japanese did not follow up their advantage, with one destroyer sunk from each
side. On November 2, the Japanese committed two heavy cruisers, two light
cruisers, and six destroyers to attack the American beachhead on Bougainville
Island. In another night action, this time at Empress Augusta Bay, an American
force of four light cruisers and eight destroyers intercepted the Japanese and
defeated them, sinking a light cruiser and a destroyer. Americans suffered no
losses, with a single destroyer damaged. The Japanese had lost their tactical
advantage in night engagements. Adding to their predicament was the increasing
Allied strength in the region, demonstrated when the Second Fleet arrived at
Rabaul on November 5 with six heavy cruisers to engage American naval forces
off Bougainville; they were immediately subjected to an attack by carrier
aircraft. Four of the cruisers were damaged and forced to return to Japan for
repairs and the operation ended as a complete fiasco. This marked the end of
major IJN operations in the South Pacific and the end of Rabaul as a major
base. The conclusion that the IJN had lost its edge in night combat was
confirmed later in November at Cape St George, when a force of American
destroyers intercepted five Japanese destroyers, sinking three of them to no
loss.
Collapse of the Defensive Perimeter
(1943–44)
Admiral Isoroku Yamamoto had
been killed on April 18, 1943. The following day, Admiral Mineichi Koga
succeeded Yamamoto as Commander-in-Chief of the Combined Fleet. In May 1943,
the Japanese prepared Operation Z or the Z plan, which envisioned the use of
the IJN to counter American forces threatening the Japanese outer defense
perimeter. This line extended from the Aleutians down through Wake, the
Marshall and Gilbert Islands, Nauru, the Bismarck Archipelago, New Guinea, then
westward past Java and Sumatra to Burma. In 1943–44, Allied forces in the
Solomons began driving relentlessly to Rabaul, eventually encircling and neutralizing
the stronghold. With their position in the Solomons disintegrating, the
Japanese modified the Z Plan by eliminating the Gilbert and Marshall Islands
and the Bismarcks as vital areas to be defended. They then based their possible
actions on the defense of an inner perimeter, which included the Marianas,
Palau, Western New Guinea, and the Dutch East Indies. Meanwhile, in the Central
Pacific a major American offensive was initiated, beginning in November 1943
with landings in the Gilbert Islands. The Japanese were forced to watch
helplessly as their garrisons in the Gilberts and then the Marshalls were
crushed. The Japanese strategy of holding overextended island garrisons was
fully exposed.
In February 1944, the US Navy's
fast carrier task force attacked the major Japanese naval base of Truk during
Operation Hailstone. Although the Combined Fleet had moved its major vessels
out in time to avoid being caught at anchor in the atoll, two days of air
attacks resulted in significant losses to Japanese aircraft and merchant
shipping. The power of the American attack on Truk far surpassed that of the
Japanese attack against Pearl Harbor. The IJN was forced to abandon Truk and
was now unable to stop the Americans on any front. Consequently, the Japanese
retained their remaining strength in preparation for what they hoped would be a
decisive battle.
Though the Japanese had been
leaders in carrier development, at the beginning of the war many of the IJN's
top commanders were still battleship or "Big Gun" adherents. However,
by early 1944 these commanders had finally accepted the fact that the carrier
was the new capital ship. This realization brought with it a change in fleet
organization. On March 1, 1944, the First Mobile Fleet was created under the
command of Vice Admiral Jisaburo Ozawa. Instead of remaining in separate
fleets, most of the front-line battleships, cruisers, and destroyers joined the
carriers in the Mobile Fleet. The Japanese finally accepted the concept of
entrusting the tactical command of a task force to a carrier admiral. This had
been adopted by the Americans almost two years earlier.
Admiral Koga survived slightly
less than a year as the Commander-in-Chief of Combined fleet. In March 1944,
while en route to the Philippines from Palau, his plane disappeared in a storm.
Koga's chief of staff, Admiral Shigeru Fukudome, had also left Palau on a
separate plane and flew into the same storm. His plane crashed near Cebu, and
he was captured by Filipino guerrillas with his documents. Although the
guerrillas were quickly forced to give up their prisoner, the documents and
their coding system found their way to Allied intelligence via an American
submarine. After recovering Fukudome, the Japanese realized that their planned
operations were compromised and they needed a new one. Admiral Shigetaro
Shimada, the Chief of the Naval Staff in Tokyo, immediately began preparing a
new plan, which was based on a preliminary draft by Admiral Koga. This plan
became known as A-GO. A-GO envisioned a decisive fleet action, where the areas
for the decisive battle were deemed to be the Palaus and the Western Carolines.
It was in these areas that the Mobile Fleet, along with large numbers of
land-based aircraft, would be concentrated. If the Americans attacked the
Marianas, they would be attacked by land-based planes in that vicinity. Then
the Americans would be lured into the areas where the Mobile Fleet could defeat
them. A month after Koga's death, Admiral Soemu Toyoda become the new commander
of Combined Fleet.
Philippine
Sea
An opportunity for a decisive
battle came in June 1944, when the Americans landed on Saipan in the Marianas.
The Japanese responded with their largest carrier force of the war, the
nine-carrier Mobile Fleet, led by Shōkaku, Zuikaku, and the new armored-deck
aircraft carrier Taihō. The resulting clash, the largest carrier battle in
history, did not turn out as the Japanese had hoped. Instead, it ended in
near-total defeat and the virtual end of their carrier force.
On June 19, a series of
Japanese carrier air strikes were shattered by strong American defenses. The
same day, Shōkaku was hit by four torpedoes from the submarine Cavalla and sank
with heavy loss of life. Taihō, the most modern carrier, was also sunk due to a
single torpedo hit from the submarine Albacore. Late the next day, the Japanese
were subjected to American carrier air attack, suffering the loss of several
ships, including the carrier Hiyō. The four Japanese air strikes had involved
373 carrier aircraft, of which only 130 returned. More aircraft and their crews
were lost when Taihō and Shōkaku were sunk. After the second day of the battle,
Japanese losses were 3,000 dead, three carriers, two fleet oilers, more than
400 carrier aircraft, and around 200 land-based aircraft, plus damage to
several ships. The Americans suffered the loss of 109 dead, 123 aircraft (80 of
which ran out of fuel returning from the strike on the Japanese fleet), and
bomb damage to the battleship South Dakota.
Although this defeat was severe
in terms of the loss of the fleet carriers Taihō, Shōkaku, and Hiyō, the real
disaster was the annihilation of the carrier air groups. These losses to the
already-outnumbered IJN were irreplaceable. The IJN had spent the better part
of a year reconstituting their carrier air groups. The Americans destroyed 90%
of that airpower in two days, leaving the Japanese with only enough aircrew to
form an air group for one light carrier, returning home with 35 of about 450 aircraft
with which the Mobile Fleet had begun the battle.
Demise of the Imperial Japanese Navy
(1944–1945)
Leyte
Gulf
Even after the disaster at
Philippine Sea, the IJN was still a formidable force. Of the 12 battleships
that were available at the beginning of the war in 1941–42, nine still remained
operational, together with 14 out of the original 18 heavy cruisers. However,
efforts to rebuild the carrier force were unsuccessful since the training given
to new aviators was of a very low standard. Consequently, the new Unryū
carriers never went to sea with a full air group. This left the Japanese with a
ragtag collection of carriers, led by Zuikaku, which was the sole survivor of
the Pearl Harbor attack force. The Japanese were left with two choices: either
commit their remaining strength in an all-out offensive, or sit by while the
Americans occupied the Philippines and cut the sea lanes between Japan and
vital resources from the Dutch East Indies and Malaya. The plan devised by the
IJN was a final attempt to create a decisive battle using its last remaining
strength, the firepower of its heavy cruisers and battleships, which were to be
all committed against the American beachhead at Leyte. The Japanese planned to
use their remaining carriers as bait, in order to lure the American carriers
away from Leyte Gulf long enough for the heavy warships to enter and destroy
any American ships present.
The Japanese assembled a force
totaling four carriers, nine battleships, 13 heavy cruisers, seven light
cruisers, and 35 destroyers. The main Center Force would pass through the San
Bernardino Strait into the Philippine Sea, turn southwards, and then attack the
landing area. Two separate groups of the Southern Force would strike at the
landing area through the Surigao Strait, while the Northern Force with the
carriers was to lure the main American covering forces away from Leyte.
However, the carriers only embarked just over 100 aircraft, the equal to those
on a single American fleet carrier; the Japanese were risking annihilation. The
situation in 1944 revealed the weakness of the IJN. After departing from Brunei
Bay on October 20, the Center Force was attacked by two American submarines
which resulted in the loss of two heavy cruisers with another crippled. On the
night of October 24–25, the Southern Force, consisting of the two Fusō-class
battleships escorted by a heavy cruiser and four destroyers, attempted to enter
Leyte Gulf from the south through Surigao Strait. This action was fought at
night, where an American force of six battleships, eight cruisers, 28
destroyers, and 39 PT boats ambushed the Japanese. Utilizing radar-guided
torpedo attacks, American destroyers sank one battleship and three destroyers
while damaging the other battleship. Naval gunfire finished off the second
battleship and the heavy cruiser, with only a single Japanese destroyer
surviving. Another group, part of the Southern Force, was built around two
heavy cruisers. This force failed to coordinate its movements with the first
and subsequently arrived at Surigao Strait in the middle of the encounter, made
a haphazard torpedo attack, and retreated.
That day, after entering the
Sibuyan Sea, the Center Force was assaulted by American carrier aircraft
throughout the whole day, forcing another heavy cruiserto retire. The Americans
then targeted Musashi and sank her under a barrage of torpedo and bomb hits.
Many other ships of the Center Force were attacked, but continued on. Convinced
that their attacks had made the Center Force ineffective, the American carriers
headed north to address the newly detected threat of the Japanese carriers. Off
Cape Engaño, the Americans launched over 500 aircraft sorties at the Japanese
force, followed up by a surface group of cruisers and destroyers. All four
Japanese carriers were sunk, but this part of the Leyte plan had succeeded in
drawing the American carriers away from Leyte Gulf. On October 25, the final
major surface action fought between the Japanese and Americans fleets during
the war occurred off Samar, when the Center Force fell upon a group of American
escort carriers escorted by only destroyers and destroyer escorts. Both sides
were surprised, but the outcome looked certain since the Japanese had four
battleships, six heavy cruisers, and two light cruisers leading two destroyer
squadrons. However, they did not press home their advantage, and were content
to conduct a largely indecisive gunnery duel before breaking off. In exchange
for the loss of three heavy cruisers, Center Force sank a single escort carrier
and three escorts. Losses were extremely heavy with four carriers, three
battleships, six heavy cruisers, four light cruisers and eleven destroyers
sunk. This represented a total of 305,452 tons or 13.22 percent of the total
Japanese warship tonnage losses during the war.
After Leyte Gulf, the IJN was
finished as an effective force. The IJN was left with six battleships Hyuga,
Ise, Nagato, Haruna, Kongo and Yamato; five fleet carriers Junyo, Shinano
(never operational), Amagi, Katsuragi and the Unryu; the light carrier Ryuho;
the escort carriers Kaiyo and Shinyo; the training carrier Hosho; eight heavy
cruisers Aoba, Ashigara, Haguro, Myoko, Nachi, Takao, Kumano and Tone; nine
light cruisers Kitakami, Kiso, Isuzu, Kashima, Kashii, Yahagi, Sakawa, Oyodo
and the Yasoshima; and some twenty destroyers plus escorts, minesweepers, and
patrol vessels.
Last
Sortie
American forces landed on
Okinawa on April 1. The Imperial General Headquarters decided to use every
available resource to dislodge the enemy. A force, called Ten-Go, consisting of
the battleship Yamato, the light cruiser Yahagi and eight destroyers; Isokaze,
Hamakaze, Yukikaze, Asashimo, Kasumi, Hatsushimo, Fuyutsuki and Suzutsuki, was
assembled. Under the command of Vice-Admiral Seiichi Itō, the force was to be
used as bait to draw away as many American carrier aircraft as possible, in
order to leave Allied naval forces off Okinawa vulnerable against large scale
kamikaze attacks. The IJN was so short of fuel that Yamato had only enough to
reach Okinawa. Off Okinawa, it was planned to beach the battleship and use her
18.1 inches (46 cm) guns to support the fighting on the island. Many of the
captains of the ships were opposed to the operation, preferring to be set loose
as sea raiders.
The force departed Tokuyama on
April 6 at 16:00. At 04:00 on April 7, the Japanese force passed the Ōsumi
Peninsula into the open ocean heading south from Kyūshū. The force had
defensive formation, with Yahagi leading Yamato and the eight destroyers
deployed in a ring around the two larger ships, with each ship 1,500 m (1,600
yd) from each other and proceeding at 20 kn (23 mph; 37 km/h). At 09:00, the
destroyer Asashimo developed engine trouble and dropped out of line. At 11:15
the force turned southwest towards Okinawa. However, 15 minutes later the
Japanese were sighted by American reconnaissance aircraft. All catapult
aircraft on board the warships were ordered back to Kyūshū.
At 12:32 some 175 miles (282
km) south of Kyūshū, the force was attacked by large numbers of American
carrier aircraft. The waves of aircraft were continuous. Yahagi, Hamakaze and
Isokaze were battered by torpedoes and bombs and sunk. Yamato suffered heavy
damage and by 14:05 she started to list. A final torpedo forced her to list
further and caused an explosion which sent smoke billowing upwards, sinking her.
Asashimo fell behind and was also sunk. Four destroyers, Fuyuzuki, Suzutsuki,
Yukikaze and Hatsushimo managed to return to Sasebo. A total of 3,665 men were
lost.
* 2,498 on board Yamato, 446
on Yahagi, and 721 on board the four destroyers.
|
Imperial
Japanese Navy Warships in World War II
|
|
Type
|
Number
|
|
Battleships
|
12
|
|
Fleet
carriers
|
13
|
|
Light
carriers
|
7
|
|
Escort
carriers
|
10
|
|
Heavy
cruisers
|
18
|
|
Light
cruisers
|
25
|
|
Destroyers
|
169
|
|
Destroyer
escorts (Kaibōkan)
|
180
|
|
Sea-going
torpedo boats
|
12
|
|
Sea-going
gunboats
|
9
|
|
Submarines
|
195
|
Warships
Battleships
Japan continued to attribute
considerable prestige to battleships and endeavored to build the largest and
most powerful ships of the period. Yamato, the heaviest and most heavily armed
battleship in history, was launched in 1941. However, they only managed to
complete Yamato and Musashi, while the third member of the class Shinano was
converted to an aircraft carrier and sunk before completion. As a result of the
changing technology as well as unexpected heavy losses in aircraft carriers in
1942, plans for even larger battleships, such as the Japanese Super
Yamato-class battleships, were cancelled.
The second half of World War II
saw the last battleship duels. In the Battle of Guadalcanal on 15 November
1942, the U.S. battleships USS South Dakota and Washington fought and sank the
Japanese battleship Kirishima, at the cost of moderate topside damage to South
Dakota. For the Battle of Leyte Gulf the Japanese had to use their battleships
as the main combatants, due to the heavy losses in their carrier air wings
suffered in the earlier Battle of the Philippine Sea, which relegated the
carriers to decoys. On 25 October 1944 six battleships, led by Rear Admiral
Jesse Oldendorf of the U.S. 7th Fleet, fired upon and claimed credit for
sinking Vice Admiral Shoji Nishimura's battleships Yamashiro and Fusō during
the Battle of Surigao Strait; in fact, both battleships were fatally crippled
by torpedo attacks from destroyers before being brought under fire by
Oldendorf's battleships, and probably only Yamashiro was the target of their
fire.
Thanks to the Japanese
carriers' successfully decoy role, the Battle off Samar on 25 October 1944
during the Battle of Leyte Gulf showed battleships could still be useful.
However, persistent American air attacks, coupled with the indecision of Vice
Admiral Takeo Kurita and tenacity shown by American destroyers and destroyer
escorts saved the American escort carriers of "Taffy 3" from
destruction by the gunfire of Yamato, Kongō, Haruna, and Nagato and their
cruiser escort. Miraculously for the Americans, only one escort carrier, two
destroyers, and one destroyer escort were lost in this action.
Ultimately, the maturity of air
power spelled doom for the battleship. Battleships in the Pacific ended up
primarily performing shore bombardment and anti-aircraft defense for the
carriers. Only the fast battleships (formerly battlecruisers) of the Kongo
class saw much action due to their speed, while the slower and heavier battleships
were held in reserve for a decisive engagement of battleships versus
battleships which never happened. Yamato and Musashi were sunk by air attacks
long before coming in gun range of the American fleet.
Aircraft
Carriers
In the 1920s, the Kaga (originally
laid down as a battleship) and a similar ship, the Akagi (originally laid down
as a battlecruiser) were converted to aircraft carriers to satisfy the terms of
the Washington Naval Treaty. From 1935 to 1938, Akagi and Kaga received
extensive rebuilds to improve their aircraft handling capacity.
Japan put particular emphasis
on aircraft carriers. The Imperial Japanese Navy started the Pacific War with
10 aircraft carriers, the largest and most modern carrier fleet in the world at
that time. There were eight American aircraft carriers at the beginning of
hostilities, only three operating in the Pacific; and eight British aircraft
carriers, of which a single one operated in the Indian Ocean. A large number of
these Japanese carriers were of small size, however, in accordance with the
limitations placed upon the Navy by the London and Washington Naval
Conferences. Nonetheless, the Japanese initially had the upper hand over the
American and British, by grouping all of their fleet carriers into a single
unit known as the 1st Air Fleet or Kidō Butai ("Mobile Force"). In
the Kidō Butai, the two Shōkaku-class carriers were superior to any carrier in
the world, until the wartime appearance of the American Essex class.
* In many ways the Japanese
were in the forefront of carrier design, and in 1941, the two Shōkakus — the
culmination of prewar Japanese design — were superior to any carrier in the
world then in commission.
Following the Battle of Midway,
in which four Japanese fleet carriers were sunk, the IJN suddenly found itself
short of fleet carriers (as well as trained aircrews), robbing them of a
strategic offensive capability. The IJN consequently undertook an ambitious set
of projects to convert commercial and military vessels into carriers, such as
the Hiyō. Another conversion project, Shinano, was based on an incomplete
Yamato-class super battleship and became the largest-displacement carrier of
World War II. One exception was the Taihō, which was the only Japanese carrier
with an armored flight deck and first to incorporate a closed hurricane bow.
All three mid-war designs were sunk in 1944, with Shinano and Taihō being sunk
by U.S. submarines, and Hiyō by air attacks. The IJN also attempted to build a
number of fleet carriers called the Unryū-class, mostly based on the older
Hiryū design rather than the newer Shōkaku or Taihō for the sake of reducing
construction cost and time. Most carriers were still under construction or
cancelled by the end of the war, while the few completed ships never embarked
air groups due to severe shortages of carrier-qualified aircrew.
Destroyers
Japanese World War II
destroyers included some of the most formidable destroyers of their day. This
came as a nasty surprise to the Allies, who had generally underestimated
Japanese technical capabilities. The Japanese had reassessed their naval needs
in the mid-1920s and, placing an emphasis on ship and weapons technology and
night fighting expertise, developed a completely new destroyer design.
Subsequent development from one destroyer class to the next was not, however, a
smooth progression. Aside from the usual changes arising from experience,
serious design faults also came to light and naval treaties imposed
restrictions. As a result, the early "Special Type" destroyers
required significant changes and the specifications of subsequent classes was
reduced in one way or another. Naval treaties were later abrogated in 1937 and
so destroyer development continued without regard to limits.
Generally speaking, the Imperial
Japanese Navy (IJN) requirements gave rise to warships that were substantially
larger than their European or American equivalents, often well-equipped with
heavy torpedo armament for surface engagements but with less emphasis on
anti-aircraft or anti-submarine armament. In the early war years, their
advantages were exploited against the often second rate and poorly coordinated
Allied ships stationed in the region such as at the IJN victory in the Battle
of the Java Sea. The Japanese did not, however, continue to install new
technology, such as radar, to match their opponents, and destroyer numbers were
eroded steadily in the latter half of the Pacific War. The Japanese emphasis on
capable but expensive fleet destroyers had neglected the need for large numbers
of cheaper escort vessels (destroyer escorts or frigates) to defend critical
merchantmen, a need learnt by both the Royal Navy and the United States Navy in
the Battle of the Atlantic. In recognition that quantity was as important as
quality in some roles, design policy was therefore modified to produce units
that were easier to build and operate. Despite this, Japan's destroyer force
was halved by the end of the war. The survivors were given to the Allies.
Naval Aviation
Japan began the war with a
highly competent naval air force designed around some of the best airplanes in
the world: the A6M Zero was considered the best carrier aircraft of the
beginning of the war, the Mitsubishi G3M bomber was remarkable for its range and
speed, and the Kawanishi H8K was the world's best flying boat.* The Japanese
pilot corps at the beginning of the war were of high caliber as compared to
their contemporaries around the world due to intense training and frontline
experience in the Sino-Japanese War.** The Navy also had a competent land-based
tactical bombing force based around the Mitsubishi G3M and G4M bombers, which
astonished the world by being the first planes to sink enemy capital ships
underway, claiming battleship Prince of Wales and the battlecruiser Repulse.
* For speed and
maneuverability, for example the Zero was matchless; for range and speed few
bombers surpassed the Mitsubishi G3M, and in the Kawanishi H8K, the Japanese
navy had the world's best flying boat.
** By 1941, by training and
experience, Japan's naval aviators were undoubtedly the best among the world's
three carrier forces.
As the war progressed, the
Allies found weaknesses in Japanese naval aviation. Though most Japanese
aircraft were characterized by great operating range and agility, they had very
little in the way of defensive armament and armor. As a result, the more
numerous, heavily armed and armored American aircraft were able to develop
techniques that nullified the advantages of the Japanese aircraft. The early
carrier versus carrier naval battles in 1942 such as Coral Sea and Santa Cruz
Island were tactical victories for the IJN but they suffered disproportionately
high aircrew losses compared to the US Navy. The IJN did not have an efficient
process for rapid training of aviators, as two years of training were usually
considered necessary for a carrier flyer. Therefore, they were not able to
effectively replace seasoned pilots lost through combat attrition following
their initial successes in the Pacific campaign. The inexperience of IJN pilots
who were trained in the later part of the war was especially evident during the
Battle of the Philippine Sea, when their aircraft were shot down in droves by
the American naval pilots in what the Americans later called the "Great
Marianas Turkey Shoot". Following the Battle of Leyte Gulf, the Japanese
Navy increasingly opted towards deploying aircraft in the kamikaze role.
Although there were delays in
engine development, several new competitive aircraft designs were developed
during the war, but industrial weaknesses, lack of raw materials and
disorganization due to Allied bombing raids hampered their mass-production.
Towards the end of the conflict, several competitive plane designs were
developed, such as the 1943 Shiden, but such planes were produced too late and
in insufficient numbers (415 units for the Shiden) to affect the outcome of the
war. Radical new plane designs were also developed, such as the canard design
Shinden, and especially jet-powered aircraft such as the Nakajima Kikka and the
rocket-propelled Mitsubishi J8M Shusui. These jet designs were partially based
on technology received from Nazi Germany, usually in the form of a few drawings
only (Kikka being based on the Messerschmitt Me 262 and the J8M on the
Messerschmitt Me 163), so Japanese manufacturers had to play a key role in the
final engineering. These developments also happened too late in the conflict to
have any influence on the outcome. The Kikka only flew twice before the end of
the war.
Submarines
Japan had by far the most
varied fleet of submarines of World War II, including manned torpedoes
(Kaiten), midget submarines (Ko-hyoteki, Kairyu), medium-range submarines,
purpose-built supply submarines (many for use by the Army), long-range fleet
submarines (many of which carried an aircraft), submarines with the highest
submerged speeds of the conflict (Senkou I-201), and submarines that could
carry multiple bombers (World War II's largest submarine, the Sentoku I-400).
These submarines were also equipped with the most advanced torpedo of the
conflict, the Type 95 torpedo, a 533 mm (21 in) version of the famous 610 mm
(24 in) Type 93.
A plane from one such
long-range fleet submarine, I-25, conducted the only aerial bombing attack on
the continental United States when Warrant Flying Officer Nobuo Fujita
attempted to start massive forest fires in the Pacific Northwest outside the
town of Brookings, Oregon on September 9, 1942. Other submarines undertook
trans-oceanic yanagi missions to German-occupied Europe, such as I-30, I-8,
I-34, I-29 and I-52, in one case flying a Japanese seaplane over France in a
propaganda coup. In May 1942, Type A midget submarines were used in the attack
on Sydney Harbour and the Battle of Madagascar.
Overall however, Japanese
submarines were relatively unsuccessful. They were often used in offensive
roles against warships (in accordance with Mahanian doctrine), which were fast,
maneuverable and well-defended compared to merchant ships. In 1942, Japanese
submarines managed to sink two fleet carriers (Yorktown and Wasp), one cruiser
(Juneau), and a few destroyers and other warships, and damage several others
(aircraft carrier Saratoga). They were not able to sustain these results
afterwards, as Allied fleets were reinforced and started using better
anti-submarine tactics including those learned from the Battle of the Atlantic.
By the end of the war, submarines were instead often used to transport supplies
to island garrisons. During the war, Japan managed to sink about 1 million tons
of merchant shipping (170 ships) with her 184 submarines, compared to 1.5
million tons for Britain (493 ships), 4.65 million tons for the US (1079 ships)
and 14.5 million tons for Germany (2,000 ships) with 1,000 U-boats.
Early models were not very
maneuverable under water, could not dive very deep, and lacked radar. Later in
the war, units fitted with radar were in some instances sunk due to the ability
of US radar sets to detect their emissions. For example, USS Batfish sank three
such in the span of four days. After the end of the conflict, several of
Japan's most innovative and advanced submarines were sent to Hawaii for
inspection in "Operation Road's End" (I-400, I-401, I-201 and I-203)
before being scuttled by the U.S. Navy in 1946 when the Soviets demanded access
to the submarines as well.
|
Sinking
of merchant shipping
during World War II
|
|
Submarines
(number)
|
Ships sunk
(number)
|
Tonnage
sunk
(tons)
|
|
Germany
|
1,000
|
2,000
|
14.5 million
|
|
United
States
|
316
|
1,079
|
4.65 million
|
|
Britain
|
250
|
493
|
1.5 million
|
|
Japan
|
184
|
170
|
1 million
|
Special Attack Units
At the end of World War II,
numerous Special Attack Units were developed for suicide missions, in a
desperate move to compensate for the annihilation of the main fleet. These
units included Kamikaze ("Divine Wind") bombers, Shinyo ("Sea
Quake") suicide boats, Kairyu ("Sea Dragon") suicide midget
submarines, Kaiten ("Turn of Heaven") suicide torpedoes, and Fukuryu
("Crouching Dragon") suicide scuba divers who would swim under boats
and use explosives mounted on bamboo poles to destroy both the boat and
themselves. Kamikaze planes were particularly effective during the defense of
Okinawa, in which about 2,000 planes were sent to sink 34 warships and damage
around 364.
A considerable number of
Special Attack Units were built and stored in coastal hideouts for the
desperate defense of the Home islands, with the potential to destroy or damage
thousands of enemy warships.
Navy Land Forces
The Imperial Japanese Navy Land
Forces of World War II originated with the Special Naval Landing Forces, and
eventually consisted of the following:
Special
Naval Landing Force or Rikusentai or kaigun rikusentai or Tokubetsu Rikusentai:
the Japanese Marines
The Base
Force or Tokubetsu Konkyochitai provided services, primarily security, to naval
facilities
Defence
units or Bobitai or Boei-han: detachments of 200 to 400 men.
Guard forces
or Keibitai: detachments of 200–500 men who provide security to Imperial
Japanese Navy facilities
Pioneers or
Setsueitai built naval facilities, including airstrips, on remote islands.
Naval Civil
Engineering and Construction Units, or Kaigun Kenchiku Shisetsu Butai
The Naval
Communications Units or Tsushintai of 600–1,000 men to provide basic naval
communications and also handled encryption and decryption.
The Tokkeitai
Navy military police units were part of the naval intelligence armed branch,
with military police regular functions in naval installations and occupied
territories; they also worked with the Imperial Japanese Army's Kempeitai
military police, the Keishicho civil police and Tokko secret units in security
and intelligence services.
Personnel Strength
December 1941 — 291,359
including 1,500 pilots
July 1945 — 1,663,223
Bibliography
Dull, Paul
S. (2013) [1978]. A Battle History of the Imperial Japanese Navy (repr. ed.).
Annapolis, Maryland: Naval Institute Press.
Evans, David
C.; Peattie, Mark R. (1997). Kaigun: Strategy, Tactics, and Technology in the
Imperial Japanese Navy, 1887–1941. Annapolis, Maryland: Naval Institute Press.
Peattie,
Mark R. (2007). Sunburst: The Rise of Japanese Naval Air Power, 1909–1941.
Annapolis, Maryland: Naval Institute Press.
Parshall,
Jonathan; Tully, Anthony (2005). Shattered Sword: The Untold Story of the
Battle of Midway. Dulles, Virginia: Potomac Books.
Prados, John
(2012). Islands of Destiny: The Solomons Campaign and the Eclipse of the Rising
Sun. Dulles, Virginia: Penguin.
Prados, John
(2016). Storm Over Leyte: The Philippine Invasion and the Destruction of the
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Stille, Mark
(2014). The Imperial Japanese Navy in the Pacific War. Osprey Publishing.
Stille, Mark
(2013). The naval battles for Guadalcanal 1942: Clash for supremacy in the
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Willmott,
H.P. (2014). Empires in the Balance: Japanese and Allied Pacific Strategies to
April 1942 (reprint, 1982 ed.). Annapolis, Maryland: Naval Institute Press.
Willmott,
H.P. (1984). June 1944. New York, NY: Blandford Press.
Willmott,
H.P. (1983). The Barrier and the Javelin. Annapolis, Maryland: United States
Naval Institute Press.
Willmott,
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Y'Blood,
William T. (1981). Red Sun Setting: The Battle of the Philippine Sea.
Annapolis, Maryland: Naval Institute Press.
 |
| Admiral Isoroku Yamamoto, Imperial Japanese Navy Planning meeting photograph on battleship Nagato sometime in 1940, when he was Commander in Chief, Combined Fleet. Yamamoto was responsible for changing the IJN's strategy from a passive one to a more offensive one, with his advocacy of attacking the U.S. Pacific fleet at Pearl Harbor. Note that this is an excerpt of a larger image that shows other staff members at the meeting, including one holding the large dividers partially seen here. (Naval History & Heritage Command NH 63430) |
 |
| An Imperial Japanese Navy Mitsubishi A6M2 "Zero" fighter on the aircraft carrier Akagi during the Pearl Harbor attack mission. 7 December 1941. (U.S. Navy National Museum of Naval Aviation 1996.488.159.029) |
 |
The Japanese strike force advancing to the Indian Ocean. Ships shown from left to right are: Akagi, Sōryū, Hiryū, Hiei, Kirishima, Haruna, and Kongō. Taken from Zuikaku, 30 March 1942.
|
 |
| Aichi D3A Type 99 Kanbaku dive bombers on their way to attack United States Navy ships on May 7, 1942 during the Battle of the Coral Sea. The bomber seen across the wing is from Imperial Japanese Navy aircraft carrier Shōkaku. Note the single white stripe around the rear end of fuselage, which was Shōkaku identifier (e.g., Zuikaku identifier was a double white stripe). This photo is probably from the morning attack on the fleet oiler Neosho and destroyer Sims but could be from the unsuccessful afternoon mission to locate and attack the US Navy aircraft carriers Yorktown and Lexington. (Japanese Defense Agency, War History Section) |
 |
| The U.S. Navy aircraft carrier USS Enterprise (CV-6, left) and other ships of her screen firing at attacking Japanese carrier aircraft during the Battle of Santa Cruz, 26 October 1942. One bomb is exploding off her stern, while two Japanese dive bombers are visible directly above the carrier and towards the center of the image. In the right center is the battleship USS South Dakota, firing her starboard 5/38 anti-aircraft guns, as marked by the bright flash amidships. (U.S. National Archives 520596) |
 |
| The Japanese transport Kinugawa Maru beached and sunk on the Guadalcanal shore, in November 1943. She had been sunk by U.S. aircraft on 15 November 1942, while attempting to deliver men and supplies to Japanese forces holding the northern part of the island. Savo Island is in the distance. (Naval History & Heritage Command 80-G-K-1467-A) |
 |
| Map depicting the Battle of the Philippine Sea. |
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| Japanese battleships at Brunei, Borneo, in October 1944, photographed just prior to the Battle of Leyte Gulf. The ships are, from left to right: Musashi, Yamato, Mogami and Nagato. (Naval History & Heritage Command NH 73090) |
 |
| The sunken Japanese battleship Haruna off Koyo, Etajima, Japan, on 8 October 1945. She had been sunk by carrier plane attacks on 28 July 1945. Note the small vessel beached on her forecastle, and the tree limbs mounted on her decks and superstructure as a camouflage measure. (Naval History & Heritage Command 80-G-351726) |
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| Imperial Japanese Navy's battleship, Yamato running full-power trials in Sukumo Bay, October 30, 1941. (Archives of the Kure Maritime Museum) |
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| The Shōkaku shortly after completion in August 1941. (Hiroshima Prefecture Yamato Museum collection) |
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| Japanese naval aircraft prepare to take off from an aircraft carrier (reportedly Shokaku) to attack Pearl Harbor during the morning of 7 December 1941. Plane in the foreground is a "Zero" Fighter, in front of "Val" dive bombers. This is probably the launch of the second attack wave. (U.S. National Archives 80-G-71198) |
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| A Japanese jet fighter Kikka at the Navy Base in Patuxent River, Maryland, 1946. (U.S. Navy) |
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I-401, an Imperial Japanese Navy I-400-class submarine, the largest submarine type of World War II.
|
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| Kamikaze attack on the USS Missouri (BB-63). About to be hit by a Japanese A6M "Zero" kamikaze, while operating off Okinawa on 11 April 1945. The plane hit the ship's side below the main deck, causing minor damage and no casualties on board the battleship. A 40 mm quad gun mount's crew is in action in the lower foreground. The kamikaze on the photo has been identified as either Flight Petty Officer 2nd Class Setsuo Ishino or Flight Petty Officer 2nd Class Kenkichi Ishii. (U.S. Navy) |
