Junyo was a Hiyo-class carrier. The name is the peregrine falcon. Mitsubishi laid her down at Nagasaki on 20 March 1939 as the liner Kashiwara Maru. The Navy bought the hull on 10 February 1941. She was launched on 26 June 1941 and commissioned on 3 May 1942. She was the sister of Hiyo. On about 24,140 tons she could make about 25 knots. She was not a fast fleet carrier.
She joined the Fourth Carrier Division with the carrier Ryujo, under Rear Admiral Kakuji Kakuta. On 3 and 4 June 1942 the two carriers struck Dutch Harbor. That was the Aleutian side of the Midway operation. She was not in the carrier fight at Midway.
In October she was at the Santa Cruz Islands. Her aircraft were in the attacks on Hornet. She was not hit. The sinking of Hornet is not credited to her. After the carrier was abandoned, Makigumo and Akigumo put torpedoes into the hulk.
On 5 November 1943 the submarine Halibut torpedoed her near the Bungo Strait. Four men were killed. She was repaired at Kure. On 20 June 1944, at the Philippine Sea, two bombs hit her at about 1730. They wrecked the funnel and the mast and damaged the flight deck. She got out. Her sister Hiyo was the carrier sunk that day. Those bombs are not credited to one American ship.
On 9 December 1944, south of Japan, the submarines Redfish and Sea Devil torpedoed her. Plaice was with that group and is not credited with a hit. Nineteen men were killed. She had survivors of Musashi aboard. She made port under her own power. Repairs were abandoned. She was still anchored at Sasebo at the surrender. She was struck on 30 November 1945 and broken up there from 1 June 1946 to 1 August 1947.
American accounts of the 7 April 1943 raid off Guadalcanal often tie the dive bombers to her air group. Aaron Ward was sunk in that raid. The planes are not credited to one unit, and they were not Mitsubishi G4M level bombers.