1. The M3 trench knife was discontinued in August 1944. 2. The M3 replaced the earlier World War I-vintage Mark I trench knife in combat service. 3. Though not a true " trench knife " per se, the Fairbairn-Sykes was used for similar purposes. 4. The U . S . Army adopted the M3 Trench Knife in 1943 as its standard combat knife. 5. She watched a sergeant whose hair was matted and disheveled as he ate his food with a trench knife . 6. Hughes went on to patent his automatic trench knife in 1919, though it appears to have never interested any civilian manufacturers. 7. American-made steel scabbards for the Mark I trench knife were marked " L . F . & C . 1918 ". 8. The basic blade design was like the M4, M5, and later M7 bayonets, based on the World War II designed M3 Trench Knife . 9. The menacing looking knife used by the Night Slasher is a brass knuckles or more like a spiked knuckles, modern version of a trench knife . 10. The Mark I trench knife was replaced in Army service by the "'USMC Mark 2 Combat Knife "'aka the "'USMC Knife, Fighting Utility " '.