Once Japan could no longer expect its fleet to contest an invasion, the purpose of island defence shifted from wearing down the US Navy to damaging experienced ground forces before an invasion of the home islands. Lieutenant Colonel Kunio Nakagawa transformed Peleliu's rocky terrain into a honeycomb fortress of trenches, tunnels, caves, and covered routes, and he rejected wasteful mass charges. Defenders also targeted leaders because veteran NCOs and officers could not be replaced as easily as equipment or junior manpower. The intended result was to make a home-island assault look prohibitively expensive by consuming Allied time, material, and experienced personnel. In this interpretation, the same logic strengthened the case for using atomic bombs instead of invading, as one strategic consequence of the defensive campaign rather than its sole cause.
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Peleliu moved Japanese defence inland and targeted experience
At Peleliu, Japanese doctrine shifted from exposed beach positions toward caves, tunnels, covered routes, and the deliberate attrition of American officers and NCOs.