The 1st Marine Division found itself detached from X Corps on the 19th and placed under the operational control of General Moore of IX Corps. This was not the first time in Marine Corps history, of course, when “soldiers of the sea” have fought alongside U.S. Army units in conventional land warfare. One of the best-known occasions was in World War I, when two Marine regiments distinguished themselves in France as a brigade of the U.S. 2d Infantry Division. The Marines had been a part of X Corps in 1950, but always under tactical circumstances which permitted more or less independent operations with the support of organic aircraft. Now the Division was to be closely integrated with the other major IX Corps units, the 24th Infantry Division, the 1st Cavalry Division, the 6th ROK Division, and the 27th British Commonwealth Brigade. Marine calls for air strikes would continue to be made through JOC, as they had been since the Hungnam redeployment. General Ridgway was on hand for the planning conference held on 19 February in General Moore’s CP at Yoju and attended by officers from IX and X Corps. General Smith, Colonel McAlister, and Colonel Bowser represented the 1st Marine Division. The scheme of maneuver called for the Marines to relieve elements of X Corps and attack in a northeasterly direction from a line of departure north of Wonju (Map 6) through the Wonju basin. The object was to cut off enemy forces which had penetrated south and east of Hoengsong, and to recover control of the roads running eastward by seizing the high ground just south of the town.[91] [91] 1stMarDiv _HD_, Feb 51, 1–2, 20. In the X Corps zone to the east, on the right flank of the Marines, the 7th Infantry Division was to attack to the north along the Yongwol-Pyongchang road. On the other Marine flank would be elements of the 6th ROK Division. Simultaneous advances were planned for I Corps to the west, where patrols had found evidence that Seoul was lightly held. Two U.S. Army units were designated at the 19 February conference to support the 1st Marine Division--the 74th Truck Company and the 92d Armored Field Artillery, then en route to the Chungju area.[92] These cannoneers and their commanding officer, Lieutenant Colonel Leon F. Lavoie, USA, were well and favorably known to the Marines, having given effective support during the Chosin Reservoir operations. [92] _Ibid._