the road from Komam-ni to Haman to Chindong-ni, the only means of north–south communication west of Masan. Northwest of Komam-ni was the broken spur ridge of P'il-bong, dominated by Sibidang-san, along the Nam River. Sibidang provided an excellent observation point for the surrounding area, and US artillery emplaced in the Komam-ni area could interdict the road junction at Chungam-ni. The 35th Infantry Regiment set up positions at Sibidang-Komam-ni, in the northern part of the 25th Infantry Division defense line. The 35th Regiment line extended from a point west of Komam-ni to the Nam River and then turned east along that stream to its confluence with the Naktong River. It was a long regimental line, about , twice the length a regiment was typically assigned. The 1st Battalion, 35th Infantry, held the regiment's left flank west of Komam-ni, and the 2nd Battalion held the regimental right along the Nam River. Meanwhile, the 3rd Battalion, redesignated from the 1st Battalion, 29th Infantry, was in reserve on the road south of Chirwon, with quick access to any part of the line. To the south was the 24th Infantry Regiment; west of Chindong-ni, the 5th Regimental Combat Team (5th RCT) was on the division's left flank. On division orders, 5th RCT first held the ground above the Chindong-ni coastal road only as far as Yaban-san, but Kean soon ordered them to close the gap with the 24th Infantry northward. When the 5th RCT sent a ROK unit of 100 men under American officers to the higher slope of Sobuk-san, KPA troops already there drove them back. Kean then ordered the 5th RCT to take this ground, but it was too late; the ground was firmly in KPA hands. Prelude The KPA 6th and 7th Divisions closed on Masan, attacking the US 25th Infantry Division on multiple fronts, with the main efforts aimed at the 24th and 35th Infantry Regiments. At the same time that the KPA 7th Division was trying to penetrate the 35th Infantry positions around Sibidang and Komam-ni, the 6th Division also sent strong patrols and probing attacks against the mountainous middle part of the 25th Infantry Division line. When the division issued orders to its subordinate units to take up defensive positions west of Masan, the 2nd Battalion, 24th Infantry was still trying to seize Obong-san, the mountain ridge just west of Battle Mountain and P'il-bong, and across a gorge-like valley