was a semi-dreadnought battleship built for the Imperial Japanese Navy (IJN) during the first decade of the 20th century. She was the second battleship built in Japan and the first to use steam turbines. The ship was named for Aki Province, now a part of Hiroshima Prefecture. The ship saw no combat during World War I. Aki was disarmed and sunk as a target in 1922–24 in accordance with the terms of the Washington Naval Treaty of 1922.