In the wake of World War I, the Imperial Japanese Navy decided to pursue the “8-8” program, designed to provide Japan with eight modern battlecruisers and eight modern battleships. Because of the 1922 Washington Naval Treaty, only two of these ships (Nagato and Mutsu) were completed as designed. The follow-up Japanese designs included the Amagi class battlecruisers and the Tosa class battleships.
As designed, Kaga was to carry 10 16″ guns in 5 twin turrets, displace 40000 tons, and make 26.5 knots. Her most likely opponents would have been the American South Dakota class, which was more heavily armed and armored but much slower. Because of the intervention of the Treaty, however, construction on Kaga was suspended. The terms of the Treaty allowed the United States and Japan to convert two ships into aircraft carriers in order to match Royal Navy conversions. The Americans converted the battlecruisers Lexington and Saratoga, and the Japanese intended to convert the battlecruisers Akagi and Amagi. Kaga and her almost complete sister Tosa were slated for destruction.
At 11:58am on September 1, 1923, a massive earthquake struck Japan. The magnitude of the earthquake measured at least 7.9. Fires broke out all over Tokyo, and it is thought that over 100000 Japanese died in the earthquake and the ensuing chaos. In the wake of the earthquake, rumours spread that Korean gangs were looting the wreckage of downtown Tokyo. In spite of the protection of the Japanese Army, nearly 2000 Koreans were murdered by Japanese mobs. Amagi, in the process of conversion to an aircraft carrier, was damaged beyond repair. Kaga won a reprieve.
The aircraft carrier Kaga displaced 32000 tons, could make 28 knots, and carried about 90 aircraft. Along with Akagi, she formed the core of Japan’s interwar aircraft carrier force. In November 1941, Kaga proceeded with Akagi, Hiryu, Soryu, Shokaku, and Zuikaku on a secret mission to attack Pearl Harbor. Her aircraft helped sink West Virginia, California, Nevada, and Oklahoma on December 7. Following the Pearl Harbor raid, Kaga helped attack Australia, Rabaul, and other Allied targets.
In May 1942 the Japanese high command decided to launch an operation to seize Midway, a small island sort of near Hawaii. Akagi, Soryu, Hiryu, and the bulk of the strength of the Japanese Combined Fleet were also committed to the operation. American codebreaking revealed the Japanese force, and three USN carrier intercepted the invasion attempt. Although Japanese fighters defeated an attack by American torpedo bombers, a group of dive bombers from Hornet, Yorktown, and Enterprise found the Japanese carriers and attacked. Kaga was hit by four bombs, which started uncontrollable fires on her flight and hangar decks. Kaga’s crew was evacuated, and the ship sank a few hours after the attack. Soryu, Akagi, and Hiryu were also destroyed at the Battle of Midway.
Trivia: Part of the purpose of the Iowa class battleships was to chase down and destroy the Kongo class battlecruisers. What class of ships served as partial justification for the reactivation of the Iowa class?