Convoy Hi-81 (ヒ-81) was the designation for a formation of Japanese transports that carried soldiers bound for Singapore and the Philippines during World War II. The transports were escorted by a large force of surface combatants including the escort carriers Shinyo and Akitsu Maru which were sunk in the Yellow Sea by American submarines. Over the course of a four-day convoy battle in November 1944 nearly 7,000 Japanese were killed in action while the Americans sustained no casualties.