In 1937, passenger-cargo NAMINOUE MARU was requisitioned by the IJA from the Osaka Shosen Kaisha (OSK) Line and converted to a hospital ship. In Sep '42, she was rerated an auxiliary transport and was sunk a month later by an American submarine, In Sep '41, sister passenger-cargo ship UKISIMA MARU (originally named UKISHIMA MARU) was requisitioned from the OSK Line by the IJN and converted to an armed merchant cruiser. In Feb '45, UKISIMA MARU was rerated an auxiliary transport. In late Aug '45, in the immediate aftermath of the war, she was proceeding to Pusan, Korea, but struck a mine and sank in Maizuru Bay.