Laid down in March, 1906, Aki was a Satsuma-class semi-Dreadnought, and the second battleship ordered from Japanese shipyards. Commissioned in 1911, she was armed with four 12" (305mm), and twelve 10" (254mm) guns, although she was originally intended to be armed with all 12". She served with the First Battle Squadron for most of World War I, but saw no action. In 1922 she was disarmed and converted to a target ship to comply with the Washington Treaty. Some of her guns were installed as coastal artillery, with the remainder being scrapped in 1943. Aki was sunk by the Kongō and Hyūga on 2 September, 1924, in Tokyo Bay.