Japan: Nakajima B5N torpedo bomber aircrews pose in front of one of their aircraft on...

Kaga was an aircraft carrier built for the Imperial Japanese Navy (IJN) and was named after the former Kaga Province in present-day Ishikawa Prefecture. Originally intended to be one of two Tosa-class battleships, Kaga was converted under the terms of the Washington Naval Treaty to an aircraft carrier as the replacement for the battlecruiser Amagi, which had been damaged during the 1923 Great Kanto earthquake. Kaga was rebuilt in 1933–35, increasing her top speed, improving her exhaust systems, and adapting her flight decks to more modern, heavier aircraft. Kaga's aircraft first supported Japanese troops in China during the Shanghai Incident of 1932 and participated in the Second Sino-Japanese War in the late 1930s. With other carriers, she took part in the Pearl Harbor raid in December 1941 and the invasion of Rabaul 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 of the Dutch East Indies by Japanese forces. Following repairs, Kaga rejoined the 1st Air Fleet for the Battle of Midway in June 1942. After bombarding American forces on Midway Atoll, Kaga and three other IJN carriers were attacked by American aircraft from Midway and the carriers Enterprise, Hornet, and Yorktown. Dive bombers from Enterprise severely damaged Kaga; when it became obvious she could not be saved, she was scuttled by Japanese destroyers to prevent her from falling into enemy hands. The loss of four large attack carriers, including Kaga at Midway, was a crucial setback for Japan, and contributed significantly to Japan's ultimate defeat. In 1999, debris from Kaga including a large section of the hull was located on the ocean floor at a depth in excess of 5,000 meters (16,404 ft); 350 miles (560 km) northwest of Midway Island. The main part of the carrier's wreck has not been found.