Lieutenant Tanigawa had built his defenses around eight light and two heavy machine guns sited at the base of the hill.

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.

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 guns, bazookas, 4.2 inch chemical mortars, 60 and 80 mm mortars.

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.

The Americans, having achieved the element of surprise in their flanking maneuver, then proceeded to leisurely and methodically destroy the remaining Japanese with white phosphorus grenades and flamethrowers.

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.