Patrol 91, consisting of one platoon, left the 5th Battalion, 1st KMC (Korean Marine Corps) Regiment and departed Hill Nan1 at 1810 on 8 December. They proceeded south toward Hill 37 where one support and flank guard assumed a position in the vicinity of the hill as close to their objective as was possible. The remainder of the patrol proceeded to a site where a second support and flank squad were placed.