TOSAN MARU was completed as a passenger-cargo ship in 1938 for Settsu Shosen KK, Osaka. Requisitioned by the Imperial Army in '41, TOSAN MARU served as an attack transport for the invasion of Patani, Siam (Thailand). On 13 Dec '41, Dutch submarine Hr.Ms. O-16 (later lost) torpedoed and badly damaged TOSAN MARU and she settled to the bottom in shallow water, but was later salved. She was towed to Hong Kong and repaired from Apr until about Nov '42. In July '44. American submarines USS FLASHER (SS-249)and USS CREVALLE (SS-291) attacked, torpedoed and sank TOSAN MARU in the Luzon Strait, Philippines.