Marine operations east of the Chosin Reservoir came to an end at 1200 on the 25th with the relief of RCT-5 by the 1st Battalion, 32d Infantry, 7th Infantry Division. Corps orders called for this unit to remain under operational control of the 1st Marine Division until the assumption of command in the area by the CO, 31st Infantry. All elements of RCT-5 were to be relieved by the following noon for the mission of advancing to Yudam-ni and then passing through RCT-7 to lead the attack toward Mupyong-ni.[364] [364] 5thMar _SAR_, 18; CG 1stMarDiv msg to CO 5thMar, 2101, 25 Nov 50. This was in accordance with Division OpnO 24-50, issued at 0800 on the 26th to implement the provisions of Corps OpnO 7. The jump-off was to be at 0800 on 27 November, with the first objective the road junction at Yongnim-dong (27 road miles west of Yudam-ni), in preparation for further advance on order to the high ground about one mile south of Kogae-gol and 35 miles west of Yudam-ni. Other provisions of OpnO 24-50 were as follows: RCT-7--to seize and secure Yudam-ni without delay, and when passed through by RCT-5, to protect the Division MSR from Sinhung-ni (7 miles west of Hagaru) to Yudam-ni; RCT-5--to pass through RCT-7 west of Yudam-ni by 0800, 27 November, advance to the west and seize first objective, prepared for further advance; RCT-1--in Division reserve, to occupy positions in the vicinity of Chinhung-ni, Koto-ri and Hagaru for the protection of the MSR; 11th Marines--less detachments, to provide general support from positions in the vicinity of Yudam-ni; 41st Commando--reinforced, to move to Yudam-ni prepared for operations to the southwest to protect Division left flank; Reconnaissance Company--to move to Yudam-ni and reconnoiter to the north in co-ordination with operations of RCT-7.[365] [365] 1stMarDiv _OpnO 24-50_, 26 Nov 50. [Illustration: USN Photo 421351 _Operation Yo-Yo--Back and forth, changing course at twelve-hour intervals, the ships bearing the Marines and their gear mark time during mine clearance operations at Wonsan._ ] [Illustration: USA Photo SC 351586 ] _Wonsan Arrivals--Above, Bob Hope entertaining Marine airmen who were first to reach the seaport; and, below, Marine infantry disembarking from cargo nets of_ Marine Phoenix _into the LCVPs_. [Illustration: USN Photo 421451 ] [Illustration: USN Photo 421319 USN Photo 421362 ] _Administrative Landing--Above, an LCM and a troop-laden amtrac in Wonsan harbor; and, below, LSTs drawn up abreast to land the thousands of tons of supplies required by a division._ [Illustration: USN Photo 421388 ]