The 41 cm/45 3rd Year Type naval gun is a 41-centimeter (16.1 in) breech-loading naval gun designed during World War I for the Imperial Japanese Navy. It served as the primary armament in the Nagato-class dreadnoughts completed after the end of the war and in coast defense mountings. Two turrets and their guns were salvaged during the 1970s from the wreck of the Japanese battleship Mutsu and are on display in Japan.

Sanshikidan was a form of ammunition: a World War II-era combined shrapnel and incendiary anti-aircraft round used by the Imperial Japanese Navy. The type of layered construction of the warheads were generically referred to as Beehive rounds. The shells were intended to put up a barrage of flame through which any aircraft attempting to attack would have to navigate. However, U.S. pilots considered these shells to be more of a pyrotechnics display than an effective anti-aircraft weapon.