Yamato was the lead ship of her class of battleships built for the Imperial Japanese Navy shortly before World War II. She and her sister ship, Musashi, were the heaviest and most powerfully armed battleships ever constructed. She was laid down in 1937 and formally commissioned a week after the Pearl Harbor attack in late 1941. Yamato was sunk by American bombers and torpedoes on April 7, 1945. Yamato and her sister Musashi carried significant weight in Japanese culture. Yamato's symbolic might was such that some Japanese citizens held the belief that their country could never fall as long as the ship was able to figh.