Japanese destroyers were fast and powerfully armed, especially in the torpedo department. Unfortunately, they were less well equipped with good sonar, radar, and adequate anti-aircraft weapons (most Japanese destroyer 5" mounts turned too slowly to track fast moving aircraft, and the dual and triple 25mm mounts which comprised the bulk of their AAA had inferior fire control, a low sustained rate of fire, and insufficient weight of shell). As a consequence, U.S. submarines and aircraft took a heavy toll of these ships. In a night fight, however, they were much to be feared.