USS Washington (BB-56) was the second and final member of the North Carolina class of fast battleships, the first vessel of the type built for the United States Navy. Built under the Washington Treaty system, North Carolina's design was limited in displacement and armament, though the United States used a clause in the Second London Naval Treaty to increase the main battery from the original armament of nine 14 in (356 mm) guns to nine 16 in (406 mm) guns. The ship was laid down in 1938 and completed in May 1941, while the United States was still neutral during World War II. Her initial career was spent training along the East Coast of the United States until after Japan attacked Pearl Harbor on 7 December 1941, bringing the United States into the war. wiki