How the sinking of Kaga and three other carriers sealed Japan’s fate in World War II

At the start of World War II, the Imperial Japanese Army (IJA) and Navy (IJN) seemed incredibly powerful and unstoppable. Their soldiers demonstrated remarkable courage and an unwavering readiness to lay down their lives for their country, while their leaders were regarded as skilled strategists. A crucial aspect of Japan’s strategy centered on using aircraft carriers to support and safeguard their pilots.

As a result, the best approach to defeating them was to concentrate on targeting and destroying these carriers.

Japanese aircraft carrier Kaga

Kaga at sea — *Kaga* was initially built as a *Tosa*-class battleship. (Photo Credit: Pictures from History / Universal Images Group / Getty Images)

Commissioned in 1921 following construction that began the previous year, Kaga was originally planned as a battleship of the Tosa-class. However, with the adoption of the Washington Naval Treaty in 1922, which allowed for the conversion of two battleship into aircraft carriers, Kaga was designated for scrapping. The Great Kantō earthquake of 1923 caused the loss of the battlecruiser Amagi, prompting a decision to convert Kaga instead of Amagi.

Kaga‘s transformation involved modifying her flight deck into three superimposed decks and making other necessary alterations. Additionally, she was equipped with a twin-gun Model B turret on each side of the middle flight deck and six casemate-mounted guns aft, along with 10 Third Year type 20 cm/50 caliber guns, previously used as the primary armament for Japan’s heavy cruisers during WWII.

Following successful sea trials, Kaga was formally commissioned into the Imperial Japanese Navy as its third aircraft carrier in November 1929, joining Akagi and Hōshō in the fleet.

Kaga‘s early service with the Imperial Japanese Navy

The United States gunboat Panay sinking. Black and white. — The United States gunboat *Panay* sinking after an attack by Japanese aircraft in the River Yangtse during the Sino-Japanese war. (Photo Credits: Eric Mayell / General Photographic Agency / Stringer / Getty Images).

After her completion, Kaga was quickly commissioned into the Navy’s 3rd Fleet, where she played a main role in supporting the Imperial Japanese Army during the 1932 Shanghai Incident. Aircraft assisting Japanese ground forces at the time were launched from both Kaga and the carrier Hōshō.

Following the Shanghai Incident, Kaga underwent several modifications, as she was considered the weaker carrier in the Imperial Japanese Navy’s fleet. She was later deployed during the Second Sino-Japanese War (1937-45), when Japan once again engaged in conflict with China. Kaga remained stationed in Japanese waters, serving as the operational base for aircraft conducting bombing missions.

The conflict ultimately ended unfavorably for Japanese forces, who surrendered to China and gave up the territory they had previously occupied.

Japanese attack on Pearl Harbor

US sailors and Marines stationed at Pearl Harbor looking at an explosion in the distance — During the Japanese attack on Pearl Harbor on December 7, 1941, *Kaga* ferried multiple dive bombers and fighter aircraft. (Photo Credit: Fox Photos / Getty Images)

In 1941, the Japanese Imperial Army tasked Marshal Admiral Isoroku Yamamoto with planning a large-scale offensive against the US Navy‘s Pacific Fleet. This wound up being the December 7 attack on Pearl Harbor, in which Kaga played a role. For the attack, the aircraft carrier had ferried 18 Mitsubishi A6M Zeros, 27 Nakajima B5Ns and 27 Aichi D3As.

The bombers and fighters that took off from Kaga were successful in their missions, scoring hits on the USS Maryland (BB-46), West Virginia (BB-48), Oklahoma (BB-37), Nevada (BB-36), California (BB-44) and Arizona (BB-39). In addition, they destroyed 20 grounded American aircraft and took out a single airborne one.

Once her mission at Pearl Harbor was complete, Kaga returned to Japan. Her work in the Pacific Theater, however, was far from over.

Kaga‘s continued World War II service

Aircraft flying over Kaga while she's at sea — Aircraft flying over *Kaga* during the Shanghai Incident in 1932. (Photo Credit: Imperial Japanese Navy / Wikimedia Commons / Public Domain)

Following the attack on Pearl Harbor, Kaga was moved to Truk, in Micronesia. From there, she supported the Battle of Rabaul, providing aircraft for the initial airstrike. In February 1942, her aircraft took part in a sortie against an American battleship in the Marshall Islands. During the effort, she ran into a reef and had to be temporarily removed from service for repairs, before returning to duty.

Kaga‘s final engagement was during the Battle of Midway. She departed from the Inland Sea at the end of May 1942, along with the rest of the Combined Fleet, and set up around 290 miles northwest of Midway Island.

On June 4, 1942, the ship was relentlessly attacked by American dive bombers. The first attempt was initially repelled by the Japanese, while the second, led by US Navy aviator C. Wade McClusky, was much more successful. Twenty-five Douglas SBD Dauntless from the USS Enterprise (CV-6) appeared over the ship, nearly undetected, and hit Kaga with a 1,000-pound bomb and multiple 500-pound bombs.

After failed attempts to repair the damage, the aircraft carrier sunk into the Pacific Ocean.

Aftermath of the Battle of Midway

Kaga docked in the water — Losing *Kaga* and three other aircraft carriers – *Akagi*, *Sōryū* and *Hiryū* – in the Battle of Midway was devastating to the Japanese (Photo Credit: Pictures from History / Universal Images Group / Getty Images)

While some sailors were rescued from Kaga, a large number perished; 811 of those aboard the vessel, many of them engineers, armorers and mechanics, were killed. That’s not to mention the number of pilots who lost their lives. Government and military officials, focused on looking invincible, were worried about news reaching the Japanese public, and the surviving sailors were snuck back into the country to prevent Midway’s story from getting out.

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The battle, itself, is seen as a turning point in the Pacific Theater. In addition to Kaga, the Imperial Japanese Navy lost three other aircraft carriers: Akagi, Sōryū and Hiryū. The loss of the vessels and the aviators who manned their aircraft significantly impacted Japan’s effectiveness, and the country’s forces were never able to recover. For many, it’s one of the major contributing factors for its defeat in the war.