The Nitta Maru was an ocean liner of the Nippon Yusen shipping line, laid down in the Mitsubishi shipyard in Nagasaki in May 1938, launched in May 1939 and commissioned on 23 March 1940. Requisitioned for use as a military transport in February 1941.
After the Battle of Midway, it was decided to convert her to an escort carrier. The conversion took place in Kure between 20 August and 25 November 1942. She was renamed Ch_y_ (Hawk Which Soars).
Her flight deck measured 150 _ 23 m (490 _ 75 ft) and was equipped with two elevators. She had no island, catapults or arresting gear.