HJMS Fuso was designed in 1911, the first Japanese super-dreadnought within the "8 x 8" program. She was the first of four twin battleships with her sister ship, Yamashiro and the "improved Fuso-class" Ise and Hyuga. Commissioned in 1915, Fuso, with 30,600 tons trial displacement and twelve 356mm guns in her main armament, was the biggest and most powerful battleship in the world.