The M3 fighting knife or M3 trench knife was an American military combat knife first issued in March 1943. The M3 was originally designated for issue to soldiers not otherwise equipped with a bayonet. However, it was particularly designed for use by elite or 'shock' forces in need of a close-combat knife such as airborne troops and Army Rangers, and these units received priority for the M3 at the start of production. As more M3 knives became available in 1943 and 1944, the knife was issued to other soldiers such as Army Air Corps crewmen and soldiers not otherwise equipped with a bayonet, including soldiers issued the M1 Carbine or submachine gun.