The battleship "Nagato" was the first dreadnought equipped with a main artillery with a caliber exceeding 400 mm. It was armed with eight 406 mm (16 in) guns. The keel of "Nagato" was laid in 1917 in the naval shipyard in Kure. The ship was launched in 1919 and incorporated into service on November 15, 1920. The sister unit was "Mutsu". Before the war, "Nagato" underwent many modifications and repairs increasing combat value of the ship. With the outbreak of World War II, "Nagato" became the flagship of Admiral Isoroku Yamamoto. The attack on Pearl Harbor was ordered from battleship's deck.

The IJN battlecruiser Kongo was laid down on January 17, 1911 at Vickers, Sons & Co. at Barrow-in-Furness. The ship's hull was launched on May 18, 1912 and on August 16, 1913 the vessel entered service with the Imperial Japanese Navy. In the years after she had been launched the Kongo had undergone two major reconstructions, each having a deep impact on the ship's characteristics and her overall arrangement.