Impressive as these figures are, they almost pall in significance compared with the meticulous planning and precision logistics required by the week-long move. It was made, without mishap, over main routes that supplied nearly a dozen other divisions on the EUSAK line and thus had to be executed so as not to interfere with combat support. Although the transfer of the 1st Marine Division from the eastern to western front was the longest transplacement of any EUSAK division, MIXMASTER was a complicated tactical maneuver that involved realignment of UNC divisions across the entire Korean front. Some 200,000 men and their combat equipment had to be relocated as part of a master plan to strengthen the Allied front and deploy more troops on line. Upon its arrival in West Korea, the 1st Marine Division was under orders to relieve the 1st ROK Division and take over a sector at the extreme left of the Eighth Army line, under I Corps control, where the weaknesses of Kimpo Peninsula defenses had been of considerable concern to EUSAK and its commander, General James A. Van Fleet. As division units reached their new sector, they moved to locations pre-selected in accordance with their assigned mission. First Marine unit into the I Corps main defensive position, the JAMESTOWN Line, was the 1st KMC Regiment attached to the division, with its organic artillery battalion. The KMCs, as well as 1/11, began to move into their new positions on 18 March. At 1400 on 20 March, the Korean Marines completed the relief of the 15th Republic of Korea Regiment in the left sector of the MLR (main line of resistance). Next into the division line, occupying the right regimental sector adjacent to the 1st Commonwealth Division, was Colonel Sidney S. Wade’s 1st Marines with three battalions forward and 2/5 attached as the regimental reserve. Relief of the 1st ROK Division was completed on the night of 24–25 March. At 0400 on 25 March the Commanding General, 1st Marine Division assumed responsibility for the defense of 32 miles of the JAMESTOWN Line. That same date the remainder of the Marine artillery battalions also relocated in their new positions.