the maritime self-defense force (msdf) had an authorized strength in 1992 of 46,000 and maintained some 44,400 personnel and operated 155 major combatants, including thirteen submarines, sixty-four destroyers and frigates, forty-three mine warfare ships and boats, eleven patrol craft, and six amphibious ships. it also flew some 205 fixed-wing aircraft and 134 helicopters. most of these aircraft were used in antisubmarine and mine warfare operations.