In late 1945, the United States Navy began introducing the
Midway-class large aircraft carriers. By contrast, the Japanese carrier fleet had been decimated during the war, but was slowly being rebuilt. By early 1947, there were eleven fleet carriers flying the Japanese flag: one
Shokaku-class, two improved-
Taiho-class (aka the
Hayataka-class), and eight
Unryu-class ships. But of these, only the two
Hayatakas were able to operate all of the latest Japanese aircraft, so a new design was desperately needed.
The new ship was of course based off the
Taihos and their successors, but incorporated various improvements, including a top-of-the-line ventilation system (the IJN had learned the hard way with
Taiho at the Battle of the Philippine Sea), which was augmented by the first deck-edge elevator system in IJN history. The number of 3.9-inch antiaircraft guns was increased to twenty in ten twin mounts, and the island was enlarged, with the bridge now able to accommodate both the ship's command staff as well as an admiral and his retinue quite nicely. In addition, the aft portion of the island no longer had the
hikocho and his men standing in an open position; they now had their own air operations center.
The resulting ship ended up being eight feet longer than the USN's
Midway-class vessels (974 feet to their 968 feet) and was essentially the Japanese answer to the American ship. The lead ship also marked a temporary departure in Japanese carrier naming convention; as the USN named their lead ship after their greatest battle (
Midway), so too did the Japanese, which was how the class came to be known as the
Tsushima-class carriers. Six ships were planned, with lead ship
Tsushima laid down in early March 1947. She was launched in late July 1948, and commissioned in early January 1949. Five sister ships followed, all carrying names of former World War II combatants:
Kaga,
Akagi,
Mutsu,
Yamato, and
Musashi. The entire class was in service by mid-July 1952.
When commissioned,
Tsushima could easily operate all four types of carrier-based aircraft from her decks: the Nakajima C6N3 reconnaissance plane, the Mitsubishi A7M3-J fighter, the Yokosuka D4Y5 dive-bomber, and the Aichi B7A3 attack aircraft. However, the carriers were forced to change with the times, and eventually all would return to their builder's yards for modifications into the IJN's first angle-decked carriers, a role in which they would operate for many years to come.
