- Class: Antarctic survey vessel and icebreaker
- Displacement: 4,365 tons
- Dimensions: x x ft.
- Machinery: 2 diesels, 2 screws, HP = 18 knots
- Builder: Matsuo Shipyard, Nagasaki
- Keel Laid: 31 Oct 1936
- Launched: 16 Feb 1938
- Completed: 10 Jun 1938
- Notes: Famed as Japan's first Antarctic observation ship. Launched as the ice-strengthened cargo ship Volochaevets intended for the USSR, she was completed for the Tatsunan Kisen Co as the Japanese cargo ship Chiyo Maru. Requisitioned by the Japanese Navy in Nov 1939 and renamed Soya 20 Feb 1940, she was rated as an auxiliary ammunition ship/survey vessel. After several surveying assignments and the outbreak of World War 2, she was part of the Midway invasion force and then assigned to Eighth Fleet in the Solomons. Survived a torpedo attack by American submarine USS Greenling 18 Jan 1943 when torpedoes exploded prematurely or were duds. At Truk during American air raids of 17-18 Feb 1944 she was lightly damaged and ran aground while trying to escape. Despite 10 KIA she returned to Japan. She survived an attack by British aircraft at Onagawa Bay 9 Aug 1945.
Postwar served as a repatriation ship and then as a lighthouse supply ship. In 1956 she underwent extensive rebuilding as an icebreaker for Antarctic observation. Shuttled between Japan and Antarctic six times, providing support for the construction of Showa Base, for Japan's first wintering team. Afterwards served as a patrol boat in Hokkaido. Taken out of service in 1978, she is now preserved at the Museum of Maritime Science, Tokyo.