Chosin Reservoir campaign began on November 27 at Yudam-ni with Chinese Communist action against the 5th and 7th Marine Regiments on the west side of the reservoir. On the 28th, the battle commenced throughout the 1st Marine Division sector. The men of the 1st Marine Division were attacked by Chinese Communist Forces whose orders were to annihilate the Marines "to the last man." When the Marines were cut off behind enemy lines and the Army had written the 1st Marine Division off as being lost because they were surrounded by 22 enemy divisions.

When an Army captain asked him for the direction of the line of retreat, Col Puller called his Tank Commander, gave them the Army position, and ordered: "If they start to pull back from that line, even one foot, I want you to open fire on them." Turning to the captain, he replied "Does that answer your question? We're here to fight." -- Chesty Puller at Koto-ri in Korea

The Marines made it out inflicting the highest casualty ratio on an enemy in history and destroying 7 entire enemy divisions in the process (An Chinese division is 16500+ men while a Marine division is 12500 men).