 Given the primary task of capturing Hill 317 , Hassett studied the approaches from the air and the ground . Two previous attempts to take Maryang San by American troops had been unsuccessful . Regardless , utilising tactics first developed against the Japanese in New Guinea during the Second World War of running along the tops of ridges , he intended to gain the advantage of the high ground , while utilising the cover afforded by the vegetation and the ease of movement along the crest @-@ lines , in order to assault the Chinese positions from unexpected directions . Meanwhile , the Chinese defenders on Maryang San were also testing a newly developed tactic called the " mobile positional defense " , in which only small units were stationed on the hills in order to exhaust the UN attackers , while the bulk of the Chinese defenders would later counterattack before the UN forces could consolidate into their newly gained positions . 
