The Pinnacle , Battle of Okinawa The Pinnacle was the name given to a 30 foot spire , atop a 450 foot ridge of coral approximately 1 , 000 yards southwest of Arakachi , Okinawa . Heavily fortified by the Japanese 62d Division , this outpost to Japan ' s main defenses at Shuri held up the U . S . 7th Division on 5 – 6 April 1945 with accurate and well - concealed machine gun , mortar and artillery fire . The Pinnacle as a defensive position . Lieutenant Tanigawa had built his defenses around eight light and two heavy machine guns sited at the base of the hill . In trenches and pits riflemen well - supplied with grenades covered the dead spaces in front of the machine guns . The defenses were connected by the usual tunnels and trenches , affording underground mobility . On the top of the ridge were four 50 mm mortars , and on the reverse slope to the south were three more . Artillery check points had been established for 62d Division field pieces to the south . Barbed wire and mine fields protected the major approaches . Lieutenant Tanigawa could hardly have hoped to stop the Americans , but undoubtedly he expected to make the price of victory high . 6 April 1945 . The U . S . Army conducted a 10 - minute artillery bombardment of The Pinnacle on the morning of 6 April . B Company , 184th Infantry , 7th Division was ordered to make a frontal assault . They were to be supported to their right ( west ) by C Company . Two platoons were able to make it close to the top of the target ridge , but alerted the Japanese defenders to their presence once the Americans began dropping grenades into the caves and underground positions they had encountered . The Japanese were able to dislodge both platoons with grenades , satchel charges and pre - sighted mortar fire . American forces suffered heavy casualties . One hour later , the Americans once again attempted a direct infantry assault against The Pinnacle ; however , this time they provided supporting 105 mm artillery fire , light tank support , anti - tank guns , heavy machine gun s , bazooka s , 4 . 2 inch chemical mortars , 60 and 80 mm mortars . Despite this combined arms assault , Japanese defenders were once again able to drive the Americans off . Japanese soldiers had simply hidden in their caves during the pre - assault bombardment , then rushed back to their prepared positions to meet subsequent assaulting troops . At this point , Lt . Col . Daniel Maybury , Commander , 1st Battalion , 184th Infantry , 7th Division , made a change in tactics . He directed C Company up a draw just beyond the ridge that had been used by B Company . While B Company quickly worked their way up the ridge in an attempt to catch Japanese defenders out of their positions , C Company worked its way up the western approaches to The Pinnacle , in what turned out to be a difficult but partially covered route . While Lieutenant Tanigawa was able to direct the repulse of B Company from the observation points afforded to him by the structure of The Pinnacle , he was completely unaware of C Company advancing on his western flank . Following in the path of supporting fire , C Company quickly made their way to the top of the ridge without loss . The Americans , having achieved the element of surprise in their flanking maneuver , then proceeded to leisurely and methodically to destroy the remaining Japanese with white phosphorus grenades and flame throwers . Only 20 of the 110 defenders escaped to the south . With the Pinnacle reduced , the entire 7th Division line could move forward . Conclusion . The Pinnacle had been a tough position to crack , yet it was only an outpost . The Pinnacle was undermanned , and no reinforcements were provided . During the action Lieutenant Tanigawa pleaded with his superiors for artillery support , but he was provided with neither the artillery nor an explanation of the refusal . By 6 – 7 April the XXIV Corps had unmasked the Shuri fortified zone , composed of many positions as fanatically defended as Pinnacle outpost and also heavily supported by artillery and fed by an almost endless stream of reinforcements from local reserve units .