Japanese aircraft carrier Kaga
Encyclopedia
Kaga (Japanese: 加賀) was an aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

 of the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...

 (IJN), named after the former Kaga Province
Kaga Province
was an old province in the area that is today the southern part of Ishikawa Prefecture. It was sometimes called .Ruled by the Maeda clan, the capital of Kaga was Kanazawa. Kaga bordered on Echizen, Etchū, Hida, and Noto Provinces...

 in present-day Ishikawa Prefecture
Ishikawa Prefecture
is a prefecture of Japan located in the Chūbu region on Honshū island. The capital is Kanazawa.- History :Ishikawa was formed from the merger of Kaga Province and the smaller Noto Province.- Geography :Ishikawa is on the Sea of Japan coast...

. Originally intended to be one of two s, Kaga was converted under the terms of the Washington Naval Treaty
Washington Naval Treaty
The Washington Naval Treaty, also known as the Five-Power Treaty, was an attempt to cap and limit, and "prevent 'further' costly escalation" of the naval arms race that had begun after World War I between various International powers, each of which had significant naval fleets. The treaty was...

 to an aircraft carrier as the replacement for the battlecruiser , which had been damaged during the 1923 Great Kanto earthquake
1923 Great Kanto earthquake
The struck the Kantō plain on the Japanese main island of Honshū at 11:58:44 am JST on September 1, 1923. Varied accounts hold that the duration of the earthquake was between 4 and 10 minutes...

. Kaga was rebuilt in 1933–35, increasing her top speed, improving her exhaust systems, and adapting her flight decks to more modern, heavier aircraft.

The third Japanese aircraft carrier to enter service, Kaga figured prominently in the development of the IJN's carrier striking force doctrine. The doctrine, which grouped carriers together to give greater mass and concentration to their air power, was a revolutionary strategic concept at the time. The employment of this doctrine was crucial in enabling Japan to attain its initial strategic goals during the first six months of the Pacific War
Pacific War
The Pacific War, also sometimes called the Asia-Pacific War refers broadly to the parts of World War II that took place in the Pacific Ocean, its islands, and in East Asia, then called the Far East...

.

Kagas aircraft first supported Japanese troops in China during the Shanghai Incident of 1932 and participated in the Second Sino-Japanese War
Second Sino-Japanese War
The Second Sino-Japanese War was a military conflict fought primarily between the Republic of China and the Empire of Japan. From 1937 to 1941, China fought Japan with some economic help from Germany , the Soviet Union and the United States...

 in the late 1930s. With other carriers, she took part in the Pearl Harbor raid in December 1941 and the invasion of Rabaul
Battle of Rabaul (1942)
The Battle of Rabaul, also known by the Japanese as Operation R, was fought on the island of New Britain in the Australian Territory of New Guinea, in January and February 1942. It was a strategically significant defeat of Allied forces by Japan in the Pacific campaign of World War II...

 in the Southwest Pacific in January 1942. The following month her aircraft participated in a combined carrier airstrike on Darwin, Australia, helping secure the conquest
Dutch East Indies campaign
The Dutch East Indies campaign of 1941–1942 was the conquest of the Dutch East Indies by forces from the Empire of Japan in the early days of the Pacific Campaign of World War II. Forces from the Allies attempted unsuccessfully to defend the islands. Indonesia was targeted by the Japanese for its...

 of the Dutch East Indies
Dutch East Indies
The Dutch East Indies was a Dutch colony that became modern Indonesia following World War II. It was formed from the nationalised colonies of the Dutch East India Company, which came under the administration of the Netherlands government in 1800....

 by Japanese forces. She missed the Indian Ocean raid
Indian Ocean raid
The Indian Ocean raid was a naval sortie by the Fast Carrier Strike Force of the Imperial Japanese Navy from 31 March-10 April 1942 against Allied shipping and bases in the Indian Ocean. It was an early engagement of the Pacific campaign of World War II...

 in April as she had to return to Japan for permanent repairs after hitting a rock in February.

After repairs Kaga rejoined the 1st Air Fleet
1st Air Fleet of the Imperial Japanese Navy
The Imperial Japanese Navy at the beginning of World War II contained the world's largest carrier fleet. At the centre, was the 1st Air Fleet which was a grouping of naval aircraft and aircraft carriers...

 for the Battle of Midway
Battle of Midway
The Battle of Midway is widely regarded as the most important naval battle of the Pacific Campaign of World War II. Between 4 and 7 June 1942, approximately one month after the Battle of the Coral Sea and six months after Japan's attack on Pearl Harbor, the United States Navy decisively defeated...

 in June 1942. After bombarding American forces on Midway Atoll
Midway Atoll
Midway Atoll is a atoll in the North Pacific Ocean, near the northwestern end of the Hawaiian archipelago, about one-third of the way between Honolulu, Hawaii, and Tokyo, Japan. Unique among the Hawaiian islands, Midway observes UTC-11 , eleven hours behind Coordinated Universal Time and one hour...

, Kaga and the other carriers were attacked by American aircraft from the carriers , , and . Dive bomber
Dive bomber
A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target reduces the distance the bomb has to fall, which is the primary factor in determining the accuracy of the drop...

s from Enterprise severely damaged Kaga; when it became obvious she could not be saved, she was scuttled
Scuttling
Scuttling is the act of deliberately sinking a ship by allowing water to flow into the hull.This can be achieved in several ways—valves or hatches can be opened to the sea, or holes may be ripped into the hull with brute force or with explosives...

 by Japanese destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

s to prevent her from falling into enemy hands. The loss of Kaga and three other IJN carriers at Midway was a crucial strategic defeat for Japan and contributed significantly to Japan's ultimate defeat in the war. In 1999, debris from Kaga was located on the ocean floor; the main body of the carrier has not yet been found.

Design and construction

Kaga was laid down as a , and was launched on 17 November 1921 at the Kawasaki Heavy Industries
Kawasaki Heavy Industries
is an international corporation based in Japan. It has headquarters in both Chūō-ku, Kobe and Minato, Tokyo.The company is named after its founder Shōzō Kawasaki and has no connection with the city of Kawasaki, Kanagawa....

 shipyard in Kobe
Kobe
, pronounced , is the fifth-largest city in Japan and is the capital city of Hyōgo Prefecture on the southern side of the main island of Honshū, approximately west of Osaka...

. On 5 February 1922 both Tosa-class ships were canceled and scheduled to be scrap
Scrap
Scrap is a term used to describe recyclable and other materials left over from every manner of product consumption, such as parts of vehicles, building supplies, and surplus materials. Unlike waste, scrap has significant monetary value...

ped under the terms of the Washington Naval Treaty
Washington Naval Treaty
The Washington Naval Treaty, also known as the Five-Power Treaty, was an attempt to cap and limit, and "prevent 'further' costly escalation" of the naval arms race that had begun after World War I between various International powers, each of which had significant naval fleets. The treaty was...

.

The Treaty authorized conversion of two battleship or battlecruiser hulls into aircraft carriers of up to 33000 long tons (33,529.7 t) standard displacement. The incomplete battlecruisers Amagi and were initially selected, but the Great Kantō Earthquake
1923 Great Kanto earthquake
The struck the Kantō plain on the Japanese main island of Honshū at 11:58:44 am JST on September 1, 1923. Varied accounts hold that the duration of the earthquake was between 4 and 10 minutes...

 of 1923 damaged Amagis hull beyond economically feasible repair, and Kaga was selected as her replacement. The formal decision to convert Kaga to an aircraft carrier was issued 13 December 1923, but no work took place until 1925 as new plans were drafted and earthquake damage to the Yokosuka Naval Arsenal
Yokosuka Naval Arsenal
was one of four principal naval shipyards owned and operated by the Imperial Japanese Navy, and was located at Yokosuka city, Kanagawa prefecture on Tokyo Bay, south of Yokohama...

 was repaired. She was officially commissioned on 31 March 1928, but this signified only the beginning of sea trials. She joined the Combined Fleet
Combined Fleet
The was the main ocean-going component of the Imperial Japanese Navy. The Combined Fleet was not a standing force, but a temporary force formed for the duration of a conflict or major naval maneuvers from various units normally under separate commands in peacetime....

 (Rengo kantai) on 30 November 1929 as the IJN's third carrier to enter service, after (1922) and Akagi (1927).

Kaga was completed with a length of 238.5 metre overall. She had a beam
Beam (nautical)
The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 of 31.67 metre and a draft at full load of 7.92 metre. She displaced 26900 long tons (27,331.7 MT) at standard load, and 33693 long tons (34,233.8 MT) at full load, nearly 6000 long tons (6,096.3 MT) less than her designed displacement as a battleship. Her complement totaled 1340 crewmembers.

Flight deck arrangements

Kaga, like Akagi, was completed with three superimposed flight decks, the only carriers ever to be designed so. The British carriers converted from "large light cruisers", , , and , each had two flight decks, but there is no evidence that the Japanese copied the British model. It is more likely that multiple decks were developed independently in the two navies as a means to launch as many aircraft as quickly as possible. Kagas main flight deck was 171.2 metre long, her middle flight deck was only about 15 metre long and started in front of the bridge, and her lower flight deck was approximately 55 metre long. The utility of her middle flight deck was questionable as it was so short that only some of the lightly loaded aircraft could use it, even in an era when the aircraft were much lighter and smaller than they were during World War II. At any rate the ever-increasing growth in aircraft performance, size and weight during the 1930s meant that even the bottom flight deck was no longer able to accommodate the take-off roll required for the new generations of aircraft being fielded and it was plated over when the ship was modernized in the mid-1930s. Kagas main flight deck was completely flat until a conning tower was added during the modernization.

As completed, the ship had two main hangar decks and a third auxiliary hangar with a total capacity of 60 aircraft. The hangars opened onto the middle and lower flight decks to allow aircraft to take off directly from the hangars while landing operations were in progress on the main flight deck above. No catapults were fitted. Her forward aircraft lift was offset to starboard and 10.67 by in size. Her aft lift was on the centerline and 12.8 by. Her arresting gear
Arresting gear
Arresting gear, or arrestor gear, is the name used for mechanical systems designed to rapidly decelerate an aircraft as it lands. Arresting gear on aircraft carriers is an essential component of naval aviation, and it is most commonly used on CATOBAR and STOBAR aircraft carriers. Similar systems...

 was a French transverse system as used on their aircraft carrier and known as the Model Fju (Fju shiki) in the Japanese service.

As originally completed, Kaga carried an air group of 28 Mitsubishi B1M3 torpedo bombers
Mitsubishi B1M
-See also:-External links:**http://www.csd.uwo.ca/~pettypi/elevon/gustin_military/db/index.html...

, 16 Nakajima A1N fighters and 16 Mitsubishi 2MR
Mitsubishi 2MR
|-See also:-External links:...

 reconnaissance aircraft.Hata, p. 24, gives the carrier's initial aircraft complement as 12 Type 3 fighters (plus three crated spares), six reconnaissance aircraft (with two spares), and 18 torpedo bombers (six spares).

Armament and armor

Kaga was armed with ten 20 cm/50 3rd Year Type guns
20 cm/50 3rd Year Type naval gun
Third year type 20 cm/50 caliber guns formed the main battery of Japan's World War II heavy cruisers. These guns were also mounted on two early aircraft carriers...

: one twin-gun Model B turret on each side of the middle flight deck and six in casemate
Casemate
A casemate, sometimes rendered casement, is a fortified gun emplacement or armored structure from which guns are fired. originally a vaulted chamber in a fortress.-Origin of the term:...

s aft. They fired 110 kilograms (242.5 lb) projectiles at a rate of three to six rounds per minute with a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...

 of 870 m/s (2,854.3 ft/s); at 25°, they had a maximum range between 22600 and 24000 m (24,715.7 and 26,246.7 yd). The Model B turrets were nominally capable of 70° elevation to provide additional anti-aircraft
Anti-aircraft warfare
NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be to protect naval, ground and air forces...

 (AA) fire, but in practice the maximum elevation was only 55°. The slow rate of fire and the fixed 5° loading angle minimized any real anti-aircraft capability. This heavy gun armament was provided in case she was surprised by enemy cruisers and forced to give battle, but her large and vulnerable flight deck, hangars, and other features made her more of a target in any surface action than a fighting warship. Carrier doctrine was still evolving at this time and the impracticability of carriers engaging in gun duels had not yet been realized.The United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 did much the same with the provision of four twin 8 inches (20 cm) gun turrets on their carriers. See Gardiner and Grey, p. 110.


She was given an anti-aircraft armament of six twin 12 centimetres (4.7 in) 45-caliber
Caliber (artillery)
In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or by extension a relative measure of the length....

 10th Year Type Model A2 gun mounts fitted on sponson
Sponson
Sponsons are projections from the sides of a watercraft, for protection, stability, or the mounting of equipment such as armaments or lifeboats, etc...

s below the level of the funnels, where they could not fire across the flight deck, three mounts per side. These guns fired 20.3 kilograms (44.8 lb) projectiles at a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...

 of 825–830 m/s (2,706.7–2,723.1 ft/s); at 45° this provided a maximum range of 16000 metres (17,497.8 yd), and they had a maximum ceiling of 10000 metres (32,808.4 ft) at 75° elevation. Their effective rate of fire was 6 to 8 rounds per minute. She had two Type 89 directors to control her 20 cm guns and two Type 91 manually powered anti-aircraft directors (Kōshaki) to control her 12 cm guns.

Kagas waterline armored belt
Belt armor
Belt armor is a layer of heavy metal armor plated on to or within outer hulls of warships, typically on battleships, battlecruisers and cruisers, and on aircraft carriers converted from those types of ships....

 was reduced from 280 millimetre during her reconstruction and the upper part of her torpedo bulge
Anti-torpedo bulge
The anti-torpedo bulge is a form of passive defence against naval torpedoes that featured in warship construction in the period between the First and Second World Wars.-Theory and form:...

 was given 127 mm (5 in) of armor. Her deck armor
Deck (ship)
A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary deck is the horizontal structure which forms the 'roof' for the hull, which both strengthens the hull and serves as the primary working surface...

 was also reduced from 102 to 38 mm (4 to 1.5 in).

Propulsion

When Kaga was being designed the problem of how to deal with exhaust gases in carrier operations had not been resolved. The swiveling funnels of the had not proved successful and wind-tunnel testing had not provided an answer. As a result, Akagi and Kaga were given different exhaust systems to evaluate in real-world conditions. Kagas funnel gases were collected in a pair of long horizontal ducts which discharged at the rear of each side of the flight deck, in spite of predictions by a number of prominent naval architects that they would not keep the hot gases away from the flight deck. The predictions proved to be correct, not least because Kaga was slower than the Akagi which allowed the gases to rise and interfere with landing operations. Another drawback was that the heat of the gases made the crew's quarters located on the side of the ship by the funnels almost uninhabitable.

Kaga was completed with four Kawasaki Brown-Curtis geared turbines with a total of 91000 shp on four shafts. As a battleship her expected speed had been 26.5 knots (14.4 m/s), but the reduction in displacement from 39900 to 33693 LT (40,540.4 to 34,233.8 MT) allowed this to increase to 27.5 knots (15 m/s), as demonstrated on her sea trial
Sea trial
A sea trial is the testing phase of a watercraft . It is also referred to as a "shakedown cruise" by many naval personnel. It is usually the last phase of construction and takes place on open water, and can last from a few hours to many days.Sea trials are conducted to measure a vessel’s...

s on 15 September 1928. She had twelve Kampon Type B (Ro) boilers with a working pressure of 20 kg/cm2, although only eight were oil-fired. The other four used a mix of oil and coal. She carried 8000 long tons (8,128 MT) of fuel oil and 1700 long tons (1,727 MT) of coal to give her a range of 8000 nautical miles (14,816 km) at 14 knots (7.6 m/s).

Early service and development of carrier doctrine

On 1 December 1931 Kaga was assigned as the flagship of the First Carrier Division
First Carrier Division
was an aircraft carrier unit of the Imperial Japanese Navy's First Air Fleet. At the beginning of the Pacific Campaign of World War II, the First Carrier Division consisted of the fleet carriers Akagi and Kaga. The division participated in the Attack on Pearl Harbor and Indian Ocean Raid...

 under the command of Rear Admiral Takayoshi Katō. The First Carrier Division, along with Hōshō, departed for Chinese waters on 29 January 1932 to support Imperial Japanese Army
Imperial Japanese Army
-Foundation:During the Meiji Restoration, the military forces loyal to the Emperor were samurai drawn primarily from the loyalist feudal domains of Satsuma and Chōshū...

 troops during the Shanghai Incident as part of the IJN's 3rd Fleet
IJN 3rd Fleet
The was a fleet of the Imperial Japanese Navy, which was created on six separate occasions.-Russo-Japanese War:First established on 28 December 1903, the IJN 3rd Fleet was created by the Imperial General Headquarters as an administrative unit to manage various vessels considered too obsolete for...

.The 3rd Fleet at this time was commanded by Vice Admiral Kichisaburō Nomura
Kichisaburō Nomura
-External links:...

 (Hata, p. 299). Fighter pilot and future ace Isamu Mochizuki served in the carrier's fighter group sometime between 1929 and 1932 (Hata, p. 342).
The B1M3s carried by Kaga and Hōshō were the main bombers used during the brief combat over Shanghai.

Kagas aircraft, operating from both the carrier and a temporary base at Kunda Airfield in Shanghai, flew missions in support of Japanese ground forces throughout February 1932. During one of these missions three of Kagas Nakajima A1N2 fighters, including one piloted by future ace Toshio Kuroiwa, escorting three Mitsubishi B1M3 torpedo bombers, scored the IJN's first air-to-air combat victory on 22 February when they shot down a Boeing P-12
Boeing P-12
The Boeing P-12 or F4B was an American pursuit aircraft that was operated by the United States Army Air Corps and United States Navy.-Design and development:...

 flown by an American volunteer pilot.
In addition to Petty Officer 3rd Class Kuroiwa, the Kaga fighter pilots involved in the shootdown were Lieutenant Nokiji Ikuta and Seaman 1st Class Kazuo Takeo (see photo). Lieutenant Kotani, the leader of the flight of three torpedo bombers, was killed in the engagement. The American pilot was Robert Short. Sakaida, p. 97, states that Short was killed in the engagement. The Kaga aircrews received a special commendation from the 3rd Fleet commander, Vice Admiral Kichisaburō Nomura
Kichisaburō Nomura
-External links:...

, for their actions. (Peattie, pp. 50–51; Hata, pp. 24, 299) Future ace Mitsugu Mori served in Kaga's fighter unit during this time. (Hata, p. 347)
Kaga returned to home waters upon the declaration of the cease-fire on 3 March and resumed fleet training with the rest of the Combined Fleet.

At this time, the IJN's developing carrier doctrine was still in its earliest stages. Kaga and the IJN's other carriers were initially given roles as tactical force multipliers supporting the fleets's battleships in the IJN's "decisive battle
Kantai kessen
The was a naval strategy adopted by the Imperial Japanese Navy following the Russo-Japanese War. It called on the use of a strong battleship force, which would destroy an invading fleet as it approached Japan after suffering losses through attrition as it penetrated Japanese perimeter defenses.The...

" doctrine. In this role, Kaga's aircraft were to attack enemy battleships with bombs and torpedoes. Aerial strikes against enemy carriers were later, beginning around 1932–1933, deemed of equal importance in order to establish air superiority during the initial stages of battle. The essential component in this strategy was that the Japanese carrier aircraft must be able to strike first with a massed, pre-emptive aerial attack. As a result, in fleet training exercises the carriers began to operate together in front of or with the main battle line. The new strategy emphasized maximum speed from both the carriers and the aircraft they carried as well as larger aircraft with greater range. Thus, longer flight decks on the carriers were required in order to handle the newer, heavier aircraft which were entering service.

Kaga was soon judged inferior to Akagi because of her slower speed, smaller flight deck (64 feet (19.5 m) shorter), and problematic funnel arrangement. Because of Kaga's perceived limitations, she was given priority over Akagi for modernization. Kaga was relegated to reserve status on 20 October 1933 to begin a second major reconstruction, with an official start date of 25 June 1934.

Reconstruction

During her second reconstruction Kaga's two lower flight decks were converted into hangars and, along with the main flight deck, were extended to the bow. This increased the flight deck length to 248.55 metre and raised aircraft capacity to 90 (72 operational and 18 in storage). A third elevator forward, 11.5 metre, serviced the extended hangars. Bomb and torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...

 elevators were modified to deliver their munitions directly to the flight deck. Her arrester gear was replaced by a Japanese-designed Type 1 system. A small starboard island superstructure was also installed.

Her power plant was completely replaced as were her propellers. New Kampon multi-stage geared turbines were fitted that increased her power from 91000 shp during trials. Each had a high-pressure, a low-pressure, and a cruising turbine coupled to a single shaft. Her boilers were replaced by eight improved oil-burning models of the Kampon Type B (Ro) with a working pressure of 22 kg/cm2 at a temperature of 300 °C (572 °F). The hull was lengthened by 10.3 metre at the stern to reduce drag and she was given another torpedo bulge above the side armor abreast the upper part of the existing bulge to increase her beam and lower her center of gravity as a result of lessons learned from the Tomozuru Incident in early 1934. This raised her standard displacement significantly, from 26900 to 38200 LT (27,331.7 to 38,813.1 MT). The extra power and the extra displacement roughly offset each other and her speed increased by less than a knot, up to 28.34 knots (15.4 m/s) on trials. Her fuel storage was increased to 7500 long tons (7,620 MT) of fuel oil
Fuel oil
Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...

 which increased her endurance to 10000 nautical mile at 16 knots (8.7 m/s). The lengthy funnel ducting was replaced by a single downturned starboard funnel modeled on that used by the Akagi with a water-cooling system for the exhaust gasses and a cover that could be raised to allow the exhaust gasses to escape if the ship developed a severe list and the mouth of the funnel touched the sea. The space freed up by the removal of the funnel ducts was divided into two decks and converted into living quarters for the expanded air group. The carrier's complement increased to 1708 crewmembers.

The two twin turrets on the middle flight deck were removed and four new 20 cm/50 3rd Year Type No. 1 guns in casemates were added forward. Her 12 cm anti-aircraft guns were replaced by eight 12.7 centimetres (5 in)/40 Type 89 guns in twin mounts. They fired 23.45 kilograms (51.7 lb) projectiles at a rate between 8 and 14 rounds per minute at a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...

 of 700–725 m/s (2,296.6–2,378.6 ft/s); at 45°, this provided a maximum range of 14800 metres (16,185.5 yd), and a maximum ceiling of 9400 metres (30,839.9 ft). Their sponsons were raised one deck to allow them some measure of cross-deck fire. Eleven twin 25 mm Type 96 gun mounts were added, also on sponsons. They fired 0.25 kilogram (0.551155655462194 lb) projectiles at a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...

 of 900 m/s (2,952.8 ft/s); at 50°, this provided a maximum range of 7500 metres (8,202 yd), and an effective ceiling of 5500 metres (18,044.6 ft). The maximum effective rate of fire was only between 110 and 120 rounds per minute due to the frequent need to change the fifteen-round magazines. Six 6.5 millimetre (0.255905511811024 in) Type 11
Type 11 Light Machine Gun
The was a light machine gun used by the Imperial Japanese Army in the interwar period and during World War II.-History:Combat experience in the Russo-Japanese War of 1904-1905 had convinced the Japanese army of the utility of machine guns to provide covering fire for advancing infantry...

 machine guns were also carried. Six Type 95 directors were fitted to control the new 25 mm guns, but Kaga retained her outdated Type 91 anti-aircraft directors.

Several major weaknesses in Kaga's design were not rectified. Kaga's aviation fuel tanks were incorporated directly into the structure of the carrier, meaning that shocks to the ship, such as those caused by bomb or shell hits, would be transmitted directly to the tanks, resulting in cracks or leaks. Also, the fully enclosed structure of the new hangar decks made fire suppression difficult, at least in part because fuel vapors could accumulate in the hangars. Adding to the danger was the requirement from the Japanese carrier doctrine that aircraft be serviced, fueled, and armed whenever possible on the hangar decks rather than on the flight deck. In addition, the carrier's hangar and flight decks carried little armor protection. Furthermore, there was no redundancy in the ship's fire-extinguishing systems. These weaknesses would later be crucial factors in the loss of the ship.

China incident

Kaga returned to service in 1935 and was assigned to the Second Carrier Division
Second Carrier Division
was an aircraft carrier unit of the Imperial Japanese Navy's First Air Fleet. At the beginning of the Pacific Campaign of World War II, the Second Carrier Division consisted of the fleet carriers Sōryū and Hiryū...

. The carrier embarked a new set of aircraft, including 16 Nakajima A2N
Nakajima A2N
|-See also:-References:NotesBibliography...

 Type 90 fighters, 16 Aichi D1A
Aichi D1A
|-See also:-External links:*...

 Type 94 dive bombers, and 28 Mitsubishi B2M
Mitsubishi B2M
|-See also:-External links:**...

 Type 89 torpedo bombers.

The renewal of hostilities with China at the Marco Polo Bridge
Marco Polo Bridge Incident
The Marco Polo Bridge Incident was a battle between the Republic of China's National Revolutionary Army and the Imperial Japanese Army, often used as the marker for the start of the Second Sino-Japanese War .The eleven-arch granite bridge, Lugouqiao, is an architecturally significant structure,...

 in July 1937 found Kaga in home waters. The ship's fighter squadron completed training at Ōmura, Nagasaki
Omura, Nagasaki
is a city located in Nagasaki Prefecture, Japan. As of January 1, 2009, the city has an estimated population of 89,891. The total area is 126.33 km², and includes Nagasaki Airport.-History:...

 then helped escort ships taking army reinforcements from Japan to China. On 15 August, along with Hōshō and , the ship took station in the East China Sea
East China Sea
The East China Sea is a marginal sea east of China. It is a part of the Pacific Ocean and covers an area of 1,249,000 km² or 750,000 square miles.-Geography:...

 as part of the 3rd Fleet and began supporting Japanese military operations along the central China coast around Shanghai and further inland.

Kaga aircraft fought their first battle on 16 August 1937 when six Type 90 fighters engaged four Chinese aircraft over Kiangwan
Jiangwan Airport
Jiangwan Airport is a former airport, located in the northeast part of Shanghai in the People’s Republic of China. The airport was redeveloped and the land is currently part of the urban area of the city.-History:...

, shooting down three without loss. Between 17 August and 7 September, Kagas Type 90 and two Mitsubishi A5M
Mitsubishi A5M
The Mitsubishi A5M, Japanese Navy designation was "Type 96 carrier-based fighter" was a Japanese carrier-based fighter aircraft. It was the world's first monoplane shipboard fighter and the direct ancestor of the famous Mitsubishi A6M 'Zero'...

 Type 96 fighters, which joined the carrier on 22 August, engaged Chinese aircraft on several more occasions. Kagas fighter pilots claimed to have shot down 10 Chinese aircraft in these encounters without loss.Lieutenant Chikamasa Igarashi led the six fighters in the 16 August engagement. Also participating in that engagement was future ace Akio Matsuba. The other engagements included: 17 August, when four Type 90s under Warrant Officer Toyoda shot down two Chinese aircraft over Kiangwan; 4 September, two Type 96 fighters under Lieutenant Tadashi Nakajima shot down three Curtiss Hawk
Curtiss Hawk
Curtiss Hawk was a name common to many aircraft designed and produced by the Curtiss Aeroplane and Motor Company, most of them fighters:-Curtiss Model 34 & Hawk I:...

s; 7 September, three Type 90s under Igarashi shot down five aircraft over T'ai Hu, with Igarashi claiming three of that number. (Hata, pp. 25–26, 263)
On 17 August twelve of the carrier's bombers attacked Hangchow without fighter escort and 11 of them were shot down by Chinese fighters. Beginning on 15 September, six Type 90 and six Type 96 fighters, 18 dive bombers, and 18 torpedo bombers were temporarily deployed to Kunda Airfield from the ship to support land operations.

On 26 September the carrier went to Sasebo
Sasebo, Nagasaki
is a city located in Nagasaki Prefecture, Japan. As of 2011, the city has an estimated population of 259,800 and the density of 609 persons per km². The total area is 426.47 km². The locality is famed for its scenic beauty. The city includes a part of Saikai National Park...

 for reprovisioning. At Sasebo, the carrier received new replacement aircraft including 32 Yokosuka B4Y
Yokosuka B4Y
-References:NotesBibliography* Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970 . ISBN 0-370-30251-6....

 Type 96 carrier attack planes (torpedo bombers), 16 Aichi D1A2 Type 96 carrier bombers (dive bombers), and 16 more Type 96 fighters. Several Nakajima A4N
Nakajima A4N
-See also:-References:NotesBibliography* Mikesh, Robert C. and Shorzoe Abe. Japanese Aircraft, 1910–1941. London: Putnam Aeronautical Books, 1990. ISBN 0-85177-840-2....

 Type 95 fighter aircraft augmented the carrier's fighter group at an unspecified later date.

Kaga returned to the front in early October 1937, and except for two brief trips to Sasebo, remained off China until December 1938. Using Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...

 (then part of the Empire of Japan
Empire of Japan
The Empire of Japan is the name of the state of Japan that existed from the Meiji Restoration on 3 January 1868 to the enactment of the post-World War II Constitution of...

) as its base, the carrier steamed 29048 nautical miles (53,796.9 km) supporting military operations from the South
South China Sea
The South China Sea is a marginal sea that is part of the Pacific Ocean, encompassing an area from the Singapore and Malacca Straits to the Strait of Taiwan of around...

 and East China Seas. During that time, Kaga bombers supported army operations by attacking enemy railroad bridges, airfields, and transportation vehicles. The carrier's fighter pilots claimed to have destroyed at least 17 Chinese aircraft in aerial combat while losing five aircraft themselves. On 12 December 1937 Kaga aircraft participated in the Panay incident
Panay incident
The USS Panay Incident was a Japanese attack on the American gunboat while she was anchored in the Yangtze River outside Nanking , China on December 12, 1937. Japan and the United States were not at war at the time. The Japanese claimed that they did not see the American flags painted on the deck...

.Six Kaga fighters were assigned to land bases near Shanghai and Nanking between 9 December 1937 and 15 January 1938. Nine fighters were temporarily based out of Nanking from 3 March through 4 April 1938. Kaga's fighter group at this time included future aces Jirō Chōno, Osamu Kudō, Yoshio Fukui, Watari Handa, Masaichi Kondō, Hatsuo Hidaka, Kiichi Oda, Satoru Ono
Satoru Ono
Satoru Ono was an officer and ace fighter pilot in the Imperial Japanese Navy during the Second Sino-Japanese War and the Pacific theater of World War II. In aerial combat over China, the Pacific, and Japan, he was officially credited with destroying eight enemy aircraft...

, and Chitoshi Isozaki. (Hata, pp. 28, 322, 346, 353, 361, 366, 368) The US Navy decrypted an IJN message which reportedly indicated that the attack on the and other neutral ships in the Yangtze River
Yangtze River
The Yangtze, Yangzi or Cháng Jiāng is the longest river in Asia, and the third-longest in the world. It flows for from the glaciers on the Tibetan Plateau in Qinghai eastward across southwest, central and eastern China before emptying into the East China Sea at Shanghai. It is also one of the...

 had been knowingly and deliberately planned by an air officer on Kaga. (Toland, p. 49)


Kaga entered the shipyard on 15 December 1938, where her arrester gear was replaced by a Type 3 system and her bridge was modernized. The flight deck and hangar areas were enlarged, increasing the carrier's aircraft capacity. The ship was completely overhauled from 15 November 1939 to 15 November 1940 before returning to active service. In the meantime, a new generation of aircraft had entered service and Kaga embarked 12 Mitsubishi A5M
Mitsubishi A5M
The Mitsubishi A5M, Japanese Navy designation was "Type 96 carrier-based fighter" was a Japanese carrier-based fighter aircraft. It was the world's first monoplane shipboard fighter and the direct ancestor of the famous Mitsubishi A6M 'Zero'...

 fighters, 24 Aichi D1A
Aichi D1A
|-See also:-External links:*...

 dive bombers and 36 Yokosuka B4Y
Yokosuka B4Y
-References:NotesBibliography* Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970 . ISBN 0-370-30251-6....

 torpedo bombers. Another 18 aircraft were carried in crates as spares.Hata, p. 27, gives Kaga's aircraft complement after overhaul as 12 fighters with four spares, 18 dive bombers with six spares, and 48 torpedo bombers with 16 spares.

The Japanese carriers' experiences off China had helped further develop the IJN's carrier doctrine. One lesson learned in China was the importance of concentration and mass in projecting naval air power ashore. Therefore, in April 1941 the IJN formed the First Air Fleet
1st Air Fleet of the Imperial Japanese Navy
The Imperial Japanese Navy at the beginning of World War II contained the world's largest carrier fleet. At the centre, was the 1st Air Fleet which was a grouping of naval aircraft and aircraft carriers...

 to combine all of its fleet carriers under a single command. On 10 April 1941 Kaga was assigned to the First Carrier Division with Akagi as part of the new carrier fleet, which also included the Second and Fifth
Fifth Carrier Division
was an aircraft carrier unit of the Imperial Japanese Navy's First Air Fleet. At the beginning of the Pacific Campaign of World War II, the Fifth Carrier Division consisted of the fleet carriers Shōkaku and Zuikaku. These two ships participated in the attack on Pearl Harbor, using their aircraft...

 carrier divisions. The IJN centered its doctrine on air strikes that combined the air groups within carrier divisions, rather than each individual carrier. When more than one carrier division was operating together, the divisions' air groups were combined with each other. This doctrine of combined, massed, carrier air attack groups was the most advanced of its kind of all the world's navies. The IJN, however, remained concerned that concentrating all of its carriers together would render them vulnerable to being wiped out all at once by a massive enemy air or surface strike. Thus, the IJN developed a compromise solution in which the fleet carriers would operate closely together within their carrier divisions but the divisions themselves would operate in loose rectangular formations, with approximately 7000 metres (7,655.3 yd) separating the carriers from each other.According to Parshall and Tully, pp. 86–87, the Japanese would not usually launch their entire carrier air groups into a single massed attack. Instead, each carrier would launch a "deckload strike" of all its aircraft that could be spotted at one time on each flight deck. Subsequent attack waves consisted of the next deckload of aircraft. Thus, 1st Air Fleet air attacks would often consist of at least two, massed waves of aircraft. Peattie (p. 152) and Jisaburō Ozawa
Jisaburo Ozawa
was an admiral in the Imperial Japanese Navy during World War II. He was the last Commander-in-Chief of Combined Fleet. Many military historians regard Ozawa as one of the most capable Japanese flag officers.-Biography:...

 (Goldstein, pp. 78–80) emphasize that the First Air Fleet was not the IJN's primary strategic striking force. The IJN still considered the First Air Fleet an integral component in the Combined Fleet's decisive battle task force centered on battleships.


Although the concentration of so many fleet carriers into a single unit was a new and revolutionary offensive strategic concept, the First Air Fleet suffered from several defensive deficiencies which gave it, in Mark Peattie
Mark Peattie
Mark R. Peattie is an American academic and Japanologist. Peattie is a specialist in modern Japanese military, naval, and imperial history.-Career:...

's words, a glass jaw': it could throw a punch but couldn't take one." Japanese carrier anti-aircraft guns and associated fire control systems had several design and configuration deficiencies which limited their effectiveness. Also, the IJN's fleet combat air patrol
Combat air patrol
Combat air patrol is a type of flying mission for fighter aircraft.A combat air patrol is an aircraft patrol provided over an objective area, over the force protected, over the critical area of a combat zone, or over an air defense area, for the purpose of intercepting and destroying hostile...

 (CAP) consisted of too few fighter aircraft and was hampered by an inadequate early warning system, including a lack of radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

. In addition, poor radio communications with the fighter aircraft inhibited effective command and control of the CAP. Furthermore, the carriers' escorting warships were not trained or deployed to provide close anti-aircraft support. These deficiencies, combined with the shipboard weaknesses previously detailed, would eventually doom Kaga and other First Air Fleet carriers.

Pearl Harbor

In November 1941 the IJN's Combined Fleet, under Isoroku Yamamoto
Isoroku Yamamoto
was a Japanese Naval Marshal General and the commander-in-chief of the Combined Fleet during World War II, a graduate of the Imperial Japanese Naval Academy and a student of Harvard University ....

, prepared to participate in Japan's initiation of a formal war with the United States by conducting a pre-emptive strike against the United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

's Pacific Fleet
United States Pacific Fleet
The United States Pacific Fleet is a Pacific Ocean theater-level component command of the United States Navy that provides naval resources under the operational control of the United States Pacific Command. Its home port is at Pearl Harbor Naval Base, Hawaii. It is commanded by Admiral Patrick M...

 base at Pearl Harbor
Pearl Harbor
Pearl Harbor, known to Hawaiians as Puuloa, is a lagoon harbor on the island of Oahu, Hawaii, west of Honolulu. Much of the harbor and surrounding lands is a United States Navy deep-water naval base. It is also the headquarters of the U.S. Pacific Fleet...

, Hawaii. On 17 November Kaga, under the command of Captain Jisaku Okada,Okada was born in Ishikawa Prefecture
Ishikawa Prefecture
is a prefecture of Japan located in the Chūbu region on Honshū island. The capital is Kanazawa.- History :Ishikawa was formed from the merger of Kaga Province and the smaller Noto Province.- Geography :Ishikawa is on the Sea of Japan coast...

 in 1893. He entered the IJN in 1911 and joined the air service in 1922. (Goldstein; Masataka Chihaya, p. 295)
loaded 100 torpedoes at Saeki Bay, Hiroshima; these torpedoes were specially designed for use in the shallow waters of the Pearl Harbor anchorage. On 19 November, Kaga and the rest of the Combined Fleet's mobile strike force (Kido Butai), under Chuichi Nagumo
Chuichi Nagumo
was a Japanese admiral in the Imperial Japanese Navy during World War II and one time commander of the Kido Butai . He committed suicide during the Battle of Saipan.-Early life:...

 and including six fleet carriers from the First, Second, and Fifth Carrier Divisions, assembled in Hitokappu Bay at Etorofu Island. The fleet departed Etorofu on 26 November and followed a course across the north-central Pacific to avoid commercial shipping lanes.The voyage to Hawaii encountered heavy seas, peaking in intensity on 3 December. On this day Kaga suffered its first war casualty when a crewmember was swept away by a wave and lost. (Werneth, p. 107)

For the attack on Pearl Harbor, Kaga carried a total of 18 Mitsubishi A6M Zero fighters
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

, 27 Nakajima B5N
Nakajima B5N
|-See also:-References:NotesBibliography* Bridgwater, H.C. and Peter Scott. Combat Colours Number 4: Pearl Harbor and Beyond, December 1941 to May 1942. Luton, Bedfordshire, UK: Guideline Publications, 2001. ISBN 0-9539040-6-7....

 torpedo bombers and 27 Aichi D3A
Aichi D3A
The , Allied reporting name "Val") was a World War II carrier-borne dive bomber of the Imperial Japanese Navy . It was the primary dive bomber in the Imperial Japanese Navy, and participated in almost all actions, including Pearl Harbor....

The Allied reporting name
World War II Allied names for Japanese aircraft
The World War II Allied names for Japanese aircraft were reporting names, often described as codenames, given by Allied personnel to Imperial Japanese aircraft during the Pacific campaign of World War II. The names were used by Allied personnel to identify Japanese aircraft for reporting and...

 for these aircraft were "Zeke", "Kate" and "Val" respectively.
dive bombers, plus three crated aircraft of each type for the operation. During the morning of 7 December 1941 Kaga aircraft participated in both First Air Fleet strikes launched against Oahu
Oahu
Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...

 from a position 230 nautical miles (426 km) north of the island. In the first strike of 213 total aircraft, 26 Kaga B5N carrier attack bombers attacked the American ships at anchor with bombs and torpedoes, escorted by nine Zeros. In the second strike of 170 aircraft, 26 Kaga D3A dive bombers targeted the airfield at Ford Island
Ford Island
Ford Island is located in the middle of Pearl Harbor, Hawaii. It is connected to the main island by the Ford Island Bridge. Before the bridge was built, Ford Island could only be reached by a ferry boat which ran at hourly intervals for cars and foot passengers. The island houses several naval...

 in the middle of the harbor while nine Zeros provided escort and attacked aircraft on the ground. A total of five B5N, four Zeros and six D3A from the ship were lost during the two strikes, along with their aircrews, a total of 31 personnel. Kagas bomber and torpedo crews claimed hits on the battleships , , , , , and . The ship's fighter pilots claimed to have shot down one US aircraft and destroyed 20 on the ground.Fourteen of the B5N in the first wave carried bombs and the other 12 torpedoes. A 15th bomb-carrying B5N aborted due to engine trouble. The bomb-carrying B5Ns were commanded by Lieutenant Commander Takahashi Hashiguchi and the torpedo-armed planes by Lieutenant Ichirō Kitajima (see photo). One B5N crewmember, Yasuji Inoue, was seriously injured by a bullet which shattered his chin. (Werneth, pp. 109, 138, 276) Five torpedo planes and two Zeros were lost in the first wave and two Zeros and the six dive bombers in the second wave (Werneth, p. 111). Future fighter ace Akira Yamamoto
Akira Yamamoto
Akira Yamamoto was an officer and ace fighter pilot in the Imperial Japanese Navy during the Second Sino-Japanese War and the Pacific theater of World War II...

 participated in the first strike wave and claimed to have shot down a small civilian aircraft over Oahu and destroyed six aircraft on the ground. Yamamoto was a member of Kaga's CAP at Midway and survived the battle. Future ace Kiyonobu Suzuki
Kiyonobu Suzuki (ace)
Kiyonobu Suzuki was a warrant officer and ace fighter pilot in the Imperial Japanese Navy during the Second Sino-Japanese War and the Pacific theater of World War II. In aerial combat over China and the Pacific he was officially credited with destroying nine enemy aircraft...

 participated in the second strike. Suzuki was also at Midway and survived. (Hata, pp. 295, 345) Kaga's fighter group was led by Yoshio Shiga
Yoshio Shiga
was an officer, ace fighter pilot, and leader in the Imperial Japanese Navy during the Second Sino-Japanese War and the Pacific theater of World War II. At the December 1941 Attack on Pearl Harbor, Shiga led one of the aircraft carrier Kaga's fighter divisions during the first strike on American...

 who unsuccessfully tried to be the first airborne in the first strike but was beaten by Akagi's fighter group leader. (Toland, p. 205)
Upon completion of the attack, the First and Fifth Carrier divisions, including Kaga, returned immediately to Japan.The Second Carrier Division with Hiryū and Soryū was diverted to support the invasion of Wake Island
Battle of Wake Island
The Battle of Wake Island began simultaneously with the Attack on Pearl Harbor and ended on 23 December 1941, with the surrender of the American forces to the Empire of Japan...

.

Pacific conquest

In January 1942, together with the rest of the First and Fifth Carrier Division
Fifth Carrier Division
was an aircraft carrier unit of the Imperial Japanese Navy's First Air Fleet. At the beginning of the Pacific Campaign of World War II, the Fifth Carrier Division consisted of the fleet carriers Shōkaku and Zuikaku. These two ships participated in the attack on Pearl Harbor, using their aircraft...

 carriers and staging out of Truk (now Chuuk) in Micronesia, Kaga supported the invasion of Rabaul
Battle of Rabaul (1942)
The Battle of Rabaul, also known by the Japanese as Operation R, was fought on the island of New Britain in the Australian Territory of New Guinea, in January and February 1942. It was a strategically significant defeat of Allied forces by Japan in the Pacific campaign of World War II...

 in the Bismarck Islands. Kaga provided 27 bomb-carrying B5N and 9 Zeros for the initial airstrike on Rabaul
Rabaul
Rabaul is a township in East New Britain province, Papua New Guinea. The town was the provincial capital and most important settlement in the province until it was destroyed in 1994 by falling ash of a volcanic eruption. During the eruption, ash was sent thousands of metres into the air and the...

 on 20 January 1942, during which one B5N was shot down by anti-aircraft fire.The B5N lost in the raid was crewed by Tatsuyasu Sugihara, Katsuo Yamamoto, and Yoichi Tanaka, who were killed. They were the first Japanese casualties in the invasion of Rabaul. (Werneth, pp. 115, 140) The First Carrier Division attacked Allied positions at nearby Kavieng
Kavieng
Kavieng is the capital of the Papua New Guinean province of New Ireland and the largest town on the island of the same name. The town is located at Balgai Bay, on the northern tip of the island. As of 2000, it had a population of 10,600....

 the following day, of which Kaga contributed nine Zeros and sixteen D3As. On the 22nd Kagas D3As and Zeros again attacked Rabaul and two dive bombers had to make emergency landings, but the crews were rescued. Kaga returned to Truk on 25 January and Rabaul and Kavieng were successfully occupied by Japanese forces by February.

On 9 February Kaga hit a reef at Palau
Palau
Palau , officially the Republic of Palau , is an island nation in the Pacific Ocean, east of the Philippines and south of Tokyo. In 1978, after three decades as being part of the United Nations trusteeship, Palau chose independence instead of becoming part of the Federated States of Micronesia, a...

 after she had unsuccessfully sortied against American carrier forces attacking
Marshalls-Gilberts raids
The Marshalls–Gilberts raids were tactical airstrikes and naval artillery attacks by United States Navy aircraft carrier and other warship forces against Imperial Japanese Navy garrisons in the Marshall and Gilbert Islands on 1 February 1942. The Japanese garrisons were under the overall command...

 the Marshall Islands
Marshall Islands
The Republic of the Marshall Islands , , is a Micronesian nation of atolls and islands in the middle of the Pacific Ocean, just west of the International Date Line and just north of the Equator. As of July 2011 the population was 67,182...

 on 1 February. The damage reduced the carrier's speed to 18 knots.Takeshi Maeda, a B5N crewmember on Kaga, states that the carrier grounded at Staring Bay in March, not at Palau in February. The discrepancy is not explained in the sources. (Werneth, p. 116) After temporary repairs, she continued to the Timor Sea
Timor Sea
The Timor Sea is a relatively shallow sea bounded to the north by the island of Timor, to the east by the Arafura Sea, to the south by Australia and to the west by the Indian Ocean....

, where on 19 February 1942 she, with the other carriers of the First and Second Carrier Division
Second Carrier Division
was an aircraft carrier unit of the Imperial Japanese Navy's First Air Fleet. At the beginning of the Pacific Campaign of World War II, the Second Carrier Division consisted of the fleet carriers Sōryū and Hiryū...

s, launched air strikes against Darwin, Australia
Darwin, Northern Territory
Darwin is the capital city of the Northern Territory, Australia. Situated on the Timor Sea, Darwin has a population of 127,500, making it by far the largest and most populated city in the sparsely populated Northern Territory, but the least populous of all Australia's capital cities...

 from a point 100 nautical miles (185.2 km) southeast of the easternmost tip of Timor
Timor
Timor is an island at the southern end of Maritime Southeast Asia, north of the Timor Sea. It is divided between the independent state of East Timor, and West Timor, belonging to the Indonesian province of East Nusa Tenggara. The island's surface is 30,777 square kilometres...

. Kaga contributed 27 B5Ns (carrying bombs), 18 D3A, and 9 Zeros to the attack, which caught the defenders by surprise. Eight ships were sunk, including the destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

 , and fourteen more were damaged, at a cost of only one of Kagas B5Ns. In March 1942, Kaga, based out of Staring-baai
Staring-baai
Staring-baai is a bay off the southeast peninsula of Sulawesi in Indonesia. It lies slightly southeast of Kendari, the provincial capital of South East Sulawesi, where it opens to the east onto the Banda Sea....

, helped cover the invasion of Java, although her only contribution appears to have been aircraft for the 5 March 1942 airstrike on Tjilatjap. In that attack Kaga contributed 27 bomb-carrying B5N escorted by nine Zeros. The attacking aircraft bombed merchant ships in the harbor, sinking eight of them, and attacked anti-aircraft batteries and a warehouse without loss. Most of the Allied forces in the Dutch East Indies surrendered to the Japanese later in March. Kaga was unable to participate in the Indian Ocean raid
Indian Ocean raid
The Indian Ocean raid was a naval sortie by the Fast Carrier Strike Force of the Imperial Japanese Navy from 31 March-10 April 1942 against Allied shipping and bases in the Indian Ocean. It was an early engagement of the Pacific campaign of World War II...

 in April because of the damage she had received in February. Instead, she sailed for Sasebo
Sasebo, Nagasaki
is a city located in Nagasaki Prefecture, Japan. As of 2011, the city has an estimated population of 259,800 and the density of 609 persons per km². The total area is 426.47 km². The locality is famed for its scenic beauty. The city includes a part of Saikai National Park...

 on 15 March for repairs, entering drydock on 27 March. The repairs were completed on 4 May.While Kaga was in drydock on 18 April, 12 Zeros from the carrier's air group based at Kisarazu Air Field
Kisarazu Air Field
is a military aerodrome of the Japan Ground Self-Defense Force . It is located north northwest of Kisarazu in the Chiba Prefecture, Japan.-Operations:...

 participated in the failed counterattack against the US carrier forces which had launched the Doolittle raid
Doolittle Raid
The Doolittle Raid, on 18 April 1942, was the first air raid by the United States to strike the Japanese Home Islands during World War II. By demonstrating that Japan itself was vulnerable to American air attack, it provided a vital morale boost and opportunity for U.S. retaliation after the...

 bombers. The attack group, including 29 land bombers and 12 Zeros from the 26th Air Flotilla in addition to the Kaga fighters, flew east for 600 nautical miles (1,111.2 km) before turning back after being unable to locate the American carriers, which had already departed the area (Hata, p. 148). Fighter ace Masaaki Shimakawa
Masaaki Shimakawa
was a warrant officer and ace fighter pilot in the Imperial Japanese Navy during the Pacific theater of World War II. In aerial combat over the Pacific he was officially credited with destroying eight enemy aircraft with 12 or 13 assists....

 joined the carrier's fighter unit around this time (Sakaida, p. 130). After the Indian Ocean raid, Kaga was used for limited air operations training by all the First Air Fleet air units in May as the other carriers were in the shipyard for refitting. (Parshall and Tully, p. 88)

Midway raid

Concerned by the US carrier strikes in the Doolittle
Doolittle Raid
The Doolittle Raid, on 18 April 1942, was the first air raid by the United States to strike the Japanese Home Islands during World War II. By demonstrating that Japan itself was vulnerable to American air attack, it provided a vital morale boost and opportunity for U.S. retaliation after the...

, Marshall Islands, and Lae-Salamaua
Invasion of Lae-Salamaua
The Invasion of Lae-Salamaua, called Operation SR by the Japanese, was an operation by Imperial Japanese forces to occupy the Salamaua-Lae area in the Territory of New Guinea 8–13 March 1942 during the Pacific campaign of World War II...

 raids, Yamamoto determined to force the US Navy into a showdown to eliminate the American carrier threat. Yamamoto decided to invade and occupy Midway Island, which he was sure would draw out the American carrier forces to battle. The Midway invasion was codenamed by the Japanese as Operation MI.

In support of MI, on 27 May 1942, Kaga departed the Inland Sea with the Combined Fleet on her final mission, in the company of carriers Akagi, , and which constituted the First and Second Carrier Divisions. Her aircraft complement was 27 Zeros, 20 D3As, and 27 B5Ns.Nine of the Zeros were intended to be stationed on Midway after the invasion and belonged to the 6th Air Group. Two of the D3As were in crates and were either replacements for Sōryū or also members of the 6th Air Group. (Parshall and Tully, p. 451) With the fleet positioned 250 nautical miles (463 km) northwest of Midway Island at dawn on 4 June 1942, Kaga contributed eighteen D3As, commanded by Lieutenant Shōichi Ogawa, escorted by nine Zeros to the strike against the island. The carrier's B5Ns were armed with torpedoes and kept ready in case enemy ships were discovered during the Midway raid. One each of the D3As and Zeros was shot down by AA fire over Midway, and another four D3As were damaged. Kagas Zero pilots claimed to have shot down 12 US aircraft over Midway Island. One Kaga B5N was launched to augment the fleet's reconnaissance of the surrounding ocean.Twenty-five total US aircraft were lost over Midway during the air raid. (Willmott, p. 380) The reconnaissance B5N was commanded by Ensign Haruo Yoshino and covered the search leg south-southeast from the Kido Butai to the west of Midway and over Kure Atoll
Kure Atoll
Kure Atoll or Ocean Island is an atoll in the Pacific Ocean beyond Midway Atoll in the Northwestern Hawaiian Islands at . The only land of significant size is called Green Island and is habitat for hundreds of thousands of seabirds...

. The aircraft did not sight any enemy ships and landed back on Kaga minutes before the ship was hit by dive bombers. (Werneth, p. 140)
The carrier also put up two Zeros on CAP. Another five Zeros reinforced her CAP at 07:00 and the seven fighters helped to defend the Kido Butai from the first US air attackers from Midway Island at 07:10. Unknown to the Japanese, the US Navy had divined the Japanese MI plan from signals intelligence and had prepared an ambush using its three available carriers, positioned northeast of Midway.

At 07:15 Admiral Nagumo
Chuichi Nagumo
was a Japanese admiral in the Imperial Japanese Navy during World War II and one time commander of the Kido Butai . He committed suicide during the Battle of Saipan.-Early life:...

 ordered the B5Ns still on Kaga and Akagi rearmed with bombs for another attack on Midway itself. This process was limited by the number of ordnance carts used to handle the bombs and torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...

es and the limited number of ordnance elevators. Thus, the torpedoes could not be struck below until after all the bombs were moved up from their magazine
Magazine (artillery)
Magazine is the name for an item or place within which ammunition is stored. It is taken from the Arabic word "makahazin" meaning "warehouse".-Ammunition storage areas:...

, assembled and mounted on the aircraft. This process normally took about an hour and a half; more time would be required to bring the aircraft up to the flight deck and warm up and launch the strike group. Around 07:40 Nagumo reversed his order when he received a message that American carriers had been spotted. At 07:30 Kaga recovered three of her CAP.

Sinking

Kagas four remaining CAP fighters were in the process of landing when 16 Marine
United States Marine Corps
The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...

 SBD Dauntless
SBD Dauntless
The Douglas SBD Dauntless was a naval dive bomber made by Douglas during World War II. The SBD was the United States Navy's main dive bomber from mid-1940 until late 1943, when it was largely replaced by the SB2C Helldiver...

 dive-bombers from Midway, led by Lofton R. Henderson
Lofton R. Henderson
Lofton R. Henderson was a naval aviator in the United States Marine Corps during World War II. He was the commanding officer of VMSB-241 at the Battle of Midway and is recognized as the first Marine aviator to die during that battle while leading his squadron to attack the Japanese carrier...

, attacked Hiryu around 07:55 without result. Five Zeros were launched at 08:15 and three intercepted a dozen Midway-based United States Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...

 B-17 Flying Fortresses attempting to bomb the three other carriers from 20000 feet (6,096 m), but only limited damage was inflicted on the heavy bombers, although their attacks all missed. Five D3As also joined the CAP around this time. Another trio of Zeros were launched at 08:30. Kaga began landing her returning Midway strike force aboard around 08:35 and was finished by 08:50; one Zero pilot died after crash-landing his aircraft.The Zero pilot who died upon landing was Yukuo Tanaka. (Parshall and Tully, p. 196)

The five Zeros launched at 08:15 were recovered aboard at 09:10 and replaced by six more Zeros launched at 09:20. They intercepted the first US carrier aircraft to attack, TBD Devastator
TBD Devastator
The Douglas TBD Devastator was a torpedo bomber of the United States Navy, ordered in 1934, first flying in 1935 and entering service in 1937. At that point, it was the most advanced aircraft flying for the USN and possibly for any navy in the world...

 torpedo-bombers of VT-8
VT-8
Torpedo Squadron 8 was a United States Navy squadron of World War II torpedo bombers assigned initially to the Air Group operating from the aircraft carrier USS Hornet , until after her loss in October 1942 during the Battle of Santa Cruz Island...

 from the US carrier at 09:22, and shot down all 15, leaving only a single survivor, George H. Gay, Jr., treading water. Shortly thereafter, 14 Devastators from VT-6 from the US carrier , led by Eugene E. Lindsey
Eugene E. Lindsey
Eugene E. Lindsey, born in Sprague, Washington, 2 July 1905, graduated from the United States Naval Academy in 1927. After duty in Nevada and Saratoga he completed flight training in 1929, and served with a bombing squadron in Lexington and an observation squadron in Maryland...

, were spotted. They tried to sandwich Kaga, but the CAP, reinforced by another six Zeros launched by Kaga at 10:00, shot down all but four of the Devastators, and the carrier dodged the torpedoes.

Soon after the torpedo plane attacks, American carrier dive bombers arrived over the Japanese carriers almost undetected and began their dives. At 10:22, 25 SBD Dauntless dive-bombers from Enterprise, led by C. Wade McClusky
C. Wade McClusky
Rear Admiral Clarence Wade McClusky, Jr., was a United States Navy aviator during World War II. He is credited with playing a major part in the Battle of Midway...

, hit Kaga with one 1000 pounds (453.6 kg) bomb and at least three 500 pounds (226.8 kg) bombs. The first landed near her rear elevator and set the berthing compartments on fire, and the next bomb hit the forward elevator and penetrated the upper hangar, setting off explosions and fires among the armed and fueled planes on her hangar deck. Captain Okada and most of the ship's senior officers were killed by the third bomb, which hit the bridge.In addition to Okada, the hit on the bridge likely killed executive officer Captain Masao Kawaguchi, chief gunnery officer Lieutenant Commander Toyosaburō Miyano, navigator Commander Ichiji Monden, and communications officer Lieutenant Commander Hidekazu Takahashi. (Parshall and Tully, p. 235) The ship's maintenance officer, Commander Torao Yamazaki, was killed by the first bomb to hit. (Parshall and Tully, p. 234) At the time of McClusky's attack, Kaga likely had two or three Zeros on the flight deck preparing to take off for CAP duty. (Parshall and Tully, p. 231) Kaga anti-aircraft gunners shot down one of the dive bombers, piloted by J. Q. Roberts and the sixth to attack. This was the only dive bomber shot down by any of the Japanese carriers' anti-aircraft gunners this day (Parshall and Tully, p. 234). McClusky's bombers totalled 28 aircraft, but three split off to attack Akagi. (Lundstrom, pp. 360–361) The 1000-pound bomb hit amidships and penetrated the flight deck to explode on the upper hangar. The explosions ruptured the ship's avgas
Avgas
Avgas is an aviation fuel used to power piston-engine aircraft. Avgas is distinguished from mogas , which is the everyday gasoline used in cars and some non-commercial light aircraft...

 lines, damaged both her port and starboard fire mains and the emergency generator powering her fire pumps, as well as knocking out the carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 fire suppression system. Fueled by the avgas pouring onto the hangar deck, the fires detonated the 80000 pounds (36,287.4 kg) of bombs and torpedoes strewn across the hangar deck in a series of catastrophic multiple fuel-air explosions that blew out the hangar sides. At nearly the same time, dive bombers hit and fatally damaged Akagi and Sōryū. fired four torpedoes at the carrier; one misfired, two others missed, and one hit the burning Kaga around 14:05, but it was a dud
Dud
A dud is an ammunition round or explosive that fails to fire or detonate, respectively, on time or on command.Duds are still dangerous and have to be deactivated and disposed of carefully. Poorly designed devices A dud is an ammunition round or explosive that fails to fire or detonate,...

. (Parshall and Tully, pp. 302–03) The torpedo that hit broke in two and the warhead portion sank. The remaining, floating half was later used as a life preserver by several Kaga survivors. (Willmott, p. 427)


Unable to contain her fires, Kaga survivors were taken off by the destroyers and between 14:00 and 17:00.Parshall and Tully (p. 337) state that the two destroyers rescued over 700 of the carrier's crew. Since the carrier reportedly had a complement of 1708 (Parshall and Tully, p. 467), there should have been around 900 survivors, but the discrepancy in the numbers is not explained by the sources. Around 19:25 she was scuttled by two torpedoes from Hagikaze and sank stern-first at position 30°20′N 179°17′W. Ensign
Ensign (rank)
Ensign is a junior rank of a commissioned officer in the armed forces of some countries, normally in the infantry or navy. As the junior officer in an infantry regiment was traditionally the carrier of the ensign flag, the rank itself acquired the name....

 Takeshi Maeda, an injured Kaga B5N aircrew member rescued by Hagikaze, described the scene: "My comrade carried me up to the deck so I could see the last moments of our beloved carrier, which was nearby. Even though I was in pain tears started to run down my cheeks, and everyone around me was crying; it was a very sad sight."

The carrier's crew suffered 811 fatalities, mainly among the aircraft mechanics and armorers stationed on the hangar decks and the ship's engineers, many of whom were trapped below in the boiler and engine rooms by uncontrolled fires raging on the decks above them. Twenty-one of the ship's aviators were killed.Peattie, p. 338, states that eight Kaga airmen were killed in the air and 13 died aboard the ship. Of the 15 Kaga CAP Zeros airborne at the time the carrier was hit, five were destroyed in aerial combat and the remainder were recovered by Hiryū. Two subsequently participated in the second Hiryū airstrike on Yorktown
USS Yorktown (CV-5)
was an aircraft carrier commissioned in the United States Navy from 1937 until she was sunk at the Battle of Midway in June 1942. She was named after the Battle of Yorktown in 1781 and the lead ship of the Yorktown class which was designed after lessons learned from operations with the large...

while four others augmented the remaining carrier's CAP. All 10 pilots survived (Parshall and Tully, pp. 502–503; Lundstrom, pp. 351, 414). The two Kaga fighter pilots who joined the attack on Yorktown were Akira Yamamoto and Makoto Bandō. (Parshall and Tully, p. 290) Four of the five pilots in the downed Kaga CAP zeros were killed. (Lundstrom, p. 363) Kaga's surviving crewmembers were restricted incommunicado to an airbase in Kyūshū for one to two months after returning to Japan to help conceal word of the Midway defeat from the Japanese public. (Werneth, p. 156) Many of the survivors were then transferred back to frontline units without being allowed to contact family. Some of the injured were quarantined in hospitals for almost a year. (Parshall and Tully, pp. 386–87)
The loss of Kaga and the three other IJN carriers at Midway (Hiryū was also sunk during the battle) was a crucial strategic defeat for Japan and contributed significantly to Japan's ultimate defeat in the war.

Wreck survey

In May 1999, the Nauticos Corporation, in partnership with the US Navy, discovered some wreckage from Kaga. They employed the research vessel during a survey of a fleet exercise area with the US Navy's recently modified SEAMAP acoustic imaging system. A follow-on search by the in September 1999 located the wreckage and took photos of it. The wreckage included a 50-foot-long section of hangar bulkhead, two 25 mm anti-aircraft gun tubs, and a landing light array. The artifacts were at a depth of 17000 feet (5,181.6 m).

External links

  • Kaga, World War II Database
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