Japan changed what its island defenses were meant to hold in place

Two Japanese attrition strategies can look similar at beach level. Under Japan's own Plan Z, defenders contested the shore to keep the bombardment fleet fixed and predictable while aircraft or the battle fleet attempted to attack it. Once Japanese naval relief was no longer a credible expectation, defenders in exposed beach positions were quickly killed by concentrated fire. Peleliu's inland system instead accepted the landing and sought to hold American ground formations in a prolonged fight, delaying their use elsewhere and buying time for defenses nearer the home islands. Both methods imposed cost, but they targeted different Allied resources and depended on very different assumptions about Japanese naval power.