Ayatosan Maru (綾戸山丸 貨物船) was a 9,788 gross ton (10,930DWT) freighter that was built by Tama Shipbuilding Co., Tamano for Mitsui & Co. Ltd. launched in 1939.

During the invasion of Malaya she was damaged by Royal Australian Air Force Lockheed Hudson light bombers and a blaze broke out which was later extinguished.

While unloading troops and supplies at Gona on 21 July 1942, she was bombed by United States Army Air Forces and Royal Australian Air Force bombers and was sunk at 8°50′S 148°50′E / 8.833°S 148.833°E / -8.833; 148.833, with the loss of forty lives and three vehicles.

She became known as "The Gona wreck" with allied patrols investigating and confirming the ship's identity.

[5] The wreck was later used to range artillery and as a bombing target by Allied forces.