Unyo began as the NYK liner Yawata Maru. Mitsubishi laid her down at Nagasaki on 14 December 1938, launched her on 31 October 1939, and finished her as a passenger ship on 31 July 1940.
The navy took her for conversion to an escort carrier. She was recommissioned at Kure on 31 May 1942. On 31 July 1942 her name was changed from Yawata Maru to Unyo. She was a Taiyo-class escort carrier, used to ferry aircraft.
Ichiro Aitoku had her from 28 January 1943 to 14 April 1943. In those eleven weeks she made three trips to Truk. She was not attacked in that time.
On 10 July 1943, north of Truk, the submarine Steelhead fired five torpedoes at her and claimed hits. Unyo's own report says she saw four torpedoes and took no damage.
On 19 January 1944, about 140 miles east-southeast of Guam, near 12°12'N, 146°26'E, USS Haddock hit her. Three torpedoes struck the starboard side, forward, and one of them was a dud. The bow structure sagged. She stayed underway, was taken to Saipan, and then crawled toward Yokosuka.
On 4 and 5 February a storm off Tateyama snapped the damaged bow off. She had to steam backward. The photograph on her ship page is from those days. She is going astern, and the bow is gone. The picture has sometimes been labeled as another carrier. It is Unyo.
She was repaired. On 17 September 1944, in convoy HI-74 after leaving Seletar, USS Barb hit her with two torpedoes on the starboard side, one in the steering compartment and one in the engine room. Those two hits killed twenty-six men. She went dead in the water. For a time she looked as if she could be saved. The sea then collapsed the shored bulkheads. The crew abandoned her about 0730. She sank by the stern at 0755, near 19°10'N, 116°35'E, about 220 miles southeast of Hong Kong. Her captain went down with her. The escorts took off hundreds of men. Counts of how many died do not agree. She was struck on 10 November 1944.
The smaller picture below shows her intact, in May 1943, on the way from Truk to Yokosuka.
