At dawn on 7 April, the Japanese force passed the Ōsumi Peninsula into the open ocean heading south from Kyūshū toward Okinawa. They shifted into a defensive formation, with "Yahagi" leading "Yamato" and the eight destroyers deployed in a ring around the two larger ships, with each ship from each other and proceeding at . One of the Japanese destroyers, , developed engine trouble and turned back. U.S. reconnaissance aircraft began to shadow the main force of ships. At 10:00, the Japanese force turned west to make it look like they were withdrawing, but at 11:30, after being detected by two American PBM Mariner flying boats, the "Yamato" fired a salvo with her bow guns using special , but could not prevent the two planes from shadowing the Japanese force. Then they turned back towards Okinawa.