Japanese minesweeper Otowa Maru (1920)

She was laid down at the shipyard of Osaka Tekkosho Sakurajima Kojo for the benefit of Nippon Suisan K.K. and launched in March 1920.[2][3] In 1921, her port of registry was changed from Hiroshima to Shimonoseki; and in 1930, to Tobata.[2] She worked as a fishing vessel until 15 September 1940 when she was requisitioned by the Imperial Japanese Navy.[2] Her conversion to an auxiliary minesweeper was started on 25 September 1940 at the Mako Naval Base and completed on 15 November 1940.[2] She was assigned to the Sasebo Guard Force until 1 September 1941 when she was assigned to the Southern Expeditionary Fleet[2] organized to invade and occupy French Indochina with Reserve Lieutenant Nagahashi Kimata (長橋喜間太) as her commanding officer.[4] She spent most of her time on patrol, conducting anti-submarine and escort duty between the ports of Sai Kung, Hong Kong, and Cam Ranh Bay.[2]

On 12 January 1945, off Cam Ranh Bay in the South China Sea (11°50′N 109°00′E), she was attacked and sunk by aircraft from Vice Admiral John S. McCain, Sr.'s Task Force 38 that had entered the South China Sea to raid Japanese shipping.[2][5] Otowa Maru was struck from the Navy List on 3 May 1947.[2]