The Japanese convoy – comprising eight destroyers and eight troop transports with an escort of approximately 100 fighters – assembled and departed from Simpson Harbour in Rabaul on 28 February. During the January operation, a course was followed that hugged the south coast of New Britain. This had made it easy to provide air cover, but being close to the airfields also made it possible for the Allied Air Forces to attack both the convoy and the airfields at the same time. This time, a route was chosen along the north coast, in the hope that the Allies would be deceived into thinking that the convoy's objective was Madang. Allied air attacks on the convoy at this point would have to fly over New Britain, allowing interdiction from Japanese air bases there, but the final leg of the voyage would be particularly dangerous, because the convoy would have to negotiate the restricted waters of the Vitiaz Strait. The Japanese named the convoy "Operation 81."