The Yamato-class battleships were the pinnacle of Japanese naval design, becoming the largest and most powerful capital ships to ever be commissioned. They were the result of Japan's unilateral withdrawal from the Washington Treaty in 1934, which allowed them to build capital ships well in excess of the 35,000 ton limit (double, in this case). Although slightly shorter than the US Iowa-class, the Yamato-class had a wider beam which highlighted the massive size of the deck. It's main armament consisted of nine 18.1-in (460-mm) Type 94 guns in three triple turrets, these being the largest naval guns ever fitted on a warship. These were capable of firing special anti-aircraft shells designed to explode smaller incendiaries along a 20-degree cone (this was largely ineffective in combat). The Yamato-class was the only Japanese battleship design to have its secondary armament not arranged in casemates, but rather in four triple turrets, one each behind the main guns, and two midships. A ring of anti-aircraft mounts was installed around the supestructure, composed of 12.7-cm and 25-mm guns. Armor protection was formidable, composed of Vickers hardened steel plates, a sloped top belt, and massive bulkheads behind the main armor belt. It was not without weaknesses, however, notably poor joints. Top speed of the Yamato ships was 27 knots, not enough to be considered fast battleships and this limited their use in the early Guadalcanal and Solomons campaigns. They were both in action as carrier escorts in the Battle of the Philippines Sea, and later as surface combatants in the Battle of Leyte Gulf. A planned third ship, the Shinano was converted into an aircraft carrier (and described separately). Although neither ship survived the war, they left a lasting legacy on popular Japanese culture, in particular the Yamato's final suicide mission which was the last major operation undertaken by the IJN in World War II. They also held the record of being the largest warships made until the USS Kitty Hawk supercarriers in the 1960s.

The Yamato was commissioned just days after Pearl Harbor and soon became the flagship of the Combined Fleet, a position it held during the Battle of Midway (but where it saw no action). After spending much of the mid-war period in various anchorages, it participated in the Battle of the Philippines Sea and in the Battle of Leyte Gulf, where it sunk a US escort carrier and a destroyer. In April 1945, it was sent on a virtual suicide mission to Okinawa but was intercepted by US naval aircraft and sunk. The Musashi was commissioned after Midway but participated in the same battles as its sister. It was sunk in the Battle of the Sibuyan Sea (one of the engagements of the Battle of Leyte Gulf).