In mid-March 1952 the 8th Army, to whom the Marines were attached, instituted "Operation Bootdrop". The operation was a massive redeployment of UN forces designed to put more Republic of Korea Army units on the Jamestown Line, the UN's Main line of resistance (MLR). The 1st Marine Division was reassigned to the far western end of the MLR defending a line that encompassed the Pyongyang to Seoul corridor. For much of the next year, in what would be termed the ""Outpost War"", action along this line consisted of small, localized actions because much of the fighting revolved around the holding and retaking of various combat outposts along the MLR, including the Battles of Bunker Hill, First Hook and Outpost Vegas. Fighting continued until the took effect on 27 July 1953. During the Korean War the division suffered combat casualties of 4,004 dead and 25,864 wounded.