At 03 : 00 , 1 September , the 9th Infantry Regiment ordered its only reserve , E Company to move west along the Yongsan @-@ Naktong River road and take a blocking position at the pass between Cloverleaf Hill and Obong @-@ ni Ridge , 3 miles ( 4 @.@ 8 km ) from the river and 6 miles ( 9 @.@ 7 km ) from Yongsan . This was the critical terrain where so much heavy fighting had taken place in the first battle of the Naktong Bulge . Fighting began at the pass at 02 : 30 when an American medium tank of A Company , 72nd Tank Battalion , knocked out a T @-@ 34 at Tugok , also called Morisil . E Company never reached its blocking position . A strong North Korean force surprised and delivered heavy automatic fire on it at 03 : 30 from positions astride the road east of the pass . The company suffered heavy casualties , including the company commander and Keiser 's aide who had accompanied the force . With the critical parts of Cloverleaf Hill and Obong @-@ ni Ridge , the best defensive terrain between Yongsan and the river , the North Koreans controlled the high ground . The US 2nd Infantry Division now had to base its defense of Yongsan on relatively poor defensive terrain , the low hills at the western edge of the town .