Mogami (最上?) was the lead ship in the four-vessel Mogami-class of heavy cruisers in the Imperial Japanese Navy. She was named after the Mogami River in Tōhoku region of Japan. The Mogami-class ships were constructed as "light cruisers" (per the Washington Naval Treaty) with five triple 6.1" dual purpose guns. They were exceptionally large for light cruisers, and the barbettes for the main battery were designed for quick refitting with twin 8" guns. In 1937 all four ships were "converted" to heavy cruisers in this fashion. Mogami served in numerous combat engagements in World War II, until she was sunk at the Battle of Leyte Gulf in October 1944.