Musashi (武蔵), named after the former Japanese province, was one of four planned Yamato-class battleships built for the Imperial Japanese Navy (IJN), beginning in the late 1930s. The Yamato-class ships were the heaviest and most powerfully armed battleships ever constructed, displacing almost 72,000 long tons (73,000 t) fully loaded and armed with nine 460-millimetre (18.1 in) main guns. Their secondary armament consisted of four 155-millimetre (6.1 in) triple-gun turrets formerly used by the Mogami-class cruisers. They were equipped with six or seven floatplanes to conduct reconnaissance.

Musashi Province was a province of Japan, which today comprises Tokyo Metropolis, most of Saitama Prefecture and part of Kanagawa Prefecture. It was sometimes called Bushū (武州). The province encompassed Kawasaki and Yokohama. Musashi bordered on Kai, Kōzuke, Sagami, Shimōsa, and Shimotsuke Provinces.