I Corps would mass evenly across the Corps' front while those moving toward IX Corps would concentrate on the front of the ROK 6th Division. For the scheduled advance to the Alabama Line east of the Hwacheon Reservoir, the X Corps/ROK III Corps boundary was to be shifted west at noon on 23 April, to give the ROK III Corps, which had been operating with only the ROK 3rd Division on line, a two-division front. The III Corps' reserve division, the ROK 7th Division, began occupying the added frontage on the 22nd, its 5th Regiment relieving the ROK 36th Regiment, 5th Division and the X Corps' right early in the evening. On 23 April, the incoming division's 3rd Regiment was to move into a gap directly above Inje between the 5th Regiment and the 35th Regiment, now the right flank unit of the 5th Division. The latter's 36th Regiment meanwhile assembled below its former position in preparation for moving west into the redrawn 5th Division zone the following day as the remainder of the ROK 7th Division came into its new area. A similar shifting of KPA forces above the X and ROK III Corps was indicated when the ROK 5th Division, previously in contact with the KPA 45th Division, III Corps above Inje, captured a member of the KPA 12th Division, V Corps. Farther east, the ROK 3rd Division, which had had almost no contact since reaching the Kansas Line, received hard local attacks that drove in its outposts and pressed its main line before easing in the evening of 22 April. Thus the KPA III Corps could be shifting west toward the reservoir and the KPA V Corps returning to the line from a point above Inje eastward. On 22 April, as I and IX Corps continued their advance toward the Wyoming Line. The progress of the attack resembled that on the previous day, IX Corps' forces making easy moves of , the two I Corps divisions being limited to shorter gains by heavier resistance. On the east flank of the advance, the Hwacheon Dam, defended so stoutly by PVA 39th Army forces only a few days earlier, fell to the 1st Korean Marine Corps Regiment (1st KMC) without a fight. But a PVA captive taken elsewhere in the 1st Marine Division zone during the afternoon told interrogators that an attack would be opened before the day was