The H-class was a series of battleship designs to fulfill the requirements of Plan Z in the late 1930s and early 1940s. The first variation, "H-39," called for six ships to be built, essentially as enlarged Bismarck-class battleships with 40.6 cm (16.0 in) guns. The "H-41" design improved the "H-39" ship with still larger main guns, with eight 42 cm (17 in) weapons.