Yamato Class Battleship - "Super Yamato"-class Battleships

"Super Yamato"-class Battleships

Two battleships of an entirely new, and larger, design were planned as a part of the 1942 fleet replenishment program. Designated as Design A-150 and initially named Warship Number 178 and Warship Number 179, plans for the ships began soon after the design of the Yamato-class was finished, probably in 1938–39. Everything was "essentially completed" sometime in 1941, but with war on the horizon, work on the battleships was halted to fill a need for additional warships, such as aircraft carriers and cruisers. The Japanese loss in the Battle of Midway, where four carriers were sunk (out of ten, to date, in the entire navy), made it certain that work on the ships would never begin. In the third volume of their Battleships series, Axis and Neutral Battleships in World War II, the authors William H. Garzke and Robert O. Dulin asserted that these ships would have been the "most powerful battleships in history" because of their massive 510 mm (20 in) main battery and extensive anti-aircraft weaponry.

Similar to the fate of papers relating to the Yamato-class, most papers and all plans relating to the class were destroyed to prevent capture at the end of the war. It is known that the final design of the ships would have had an even greater firepower and size than the Yamato-class—a main battery of six 508 mm (20.0 in) guns in three twin turrets and secondary dual purpose armament consisting of 24 99 mm (3.9 in) dual mounted guns (similar to the Akizuki-class destroyers). The displacement was to be bigger than the Yamato's, and a side armor belt of 460 mm (18 in) was planned.