POW interrogations revealed that in many instances each soldier was issued 80 rounds of small arms ammunition upon crossing the Yalu. This was his total supply. The artillery and mortars were so limited that they must reserve their fire for the front line while passing up lucrative targets in the rear areas. Some attempts were made to bring reserve stocks up to forward supply dumps about 30 miles behind the front, but not much could be accomplished with animal and human transport. A primitive communications system also accounted for CCF shortcomings. The radio net extended only down to the regimental level, and telephones only to battalions or occasionally companies. Below the battalion, communication depended on runners or such signaling devices as bugles, whistles, flares, and flashlights.[238] [238] 164-MISDI-1232, 1260, 1266, 1274, and 1275 in EUSAK _WD_, 19, 26, and 28 Nov and 1 Dec 50; ADVATIS FWD #1. Rpt 0271 in EUSAK _WD_ 4 Dec 50; X Corps _PIR 81_, Annex 2; G-2 _SAR_, 17–18. The consequence was a tactical rigidity which at times was fatal. Apparently CCF commanding officers had little or no option below the battalion level. A battalion once committed to the attack often kept on as long as its ammunition lasted, even if events indicated that it was beating out its brains against the strongest part of the opposing line. The result in many such instances was tactical suicide. After these defects are taken into full account, however, the Chinese soldier and the Korean terrain made a formidable combination. Ironically, Americans fighting the first war of the new Atomic Age were encountering conditions reminiscent of the border warfare waged by their pioneer forefathers against the Indians. These aborigines, too, were outweighed in terms of weapons and equipment. But from time immemorial the night has always been the ally of the primitive fighter, and surprise his best weapon. Thus the Americans in Korea, like their ancestors on the Western plains, could never be sure when the darkness would erupt into flame as stealthy foes seemed to spring from the very earth. CHAPTER VI The Battle of Sudong _The MSR from Hungnam to Yudam-ni--ROKs Relieved by 7th Marines--CCF Counterattack at Sudong--Two Marine Battalions Cut Off--End of NKPA Tank Regiment--The Fight for How Hill--Disappearance of CCF Remnants--Koto-ri Occupied by 7th Marines_ The coastal plain of the Songchon estuary is one of the most spacious flatlands in all North Korea. Its 100 square miles divide into two irrigation districts, which regulate cultivation in a virtual sea of rice paddies. The Songchon River, swollen by tributaries in its descent from the northern hinterland, nourishes this agricultural complex before flowing into the Sea of Japan.