An M1 Garand 12-inch bayonet refers to the M1 bayonet, a shorter, more practical combat knife created during WWII by shortening the earlier, sword-like 16-inch M1905 bayonet (which was also compatible with the Garand), resulting in a 10-inch blade ideal for close quarters; while most were cut down, original 12-inch (or uncut) M1905s for the Garand are rare and valuable collector's items, often identified by their longer fuller groove.