The Japanese perimeter was too large for the infrastructure available to sustain and fortify it uniformly. Naval assets and merchant shipping were scarce, while concrete, artillery, tanks, and other defensive systems also had to be rationed across many islands. Early doctrine compounded the shortage by placing defenders on every strip of beach, where battleships and cruisers could engage them directly. These limitations help explain why later island campaigns produced uneven resistance and why Japan eventually shifted toward defence in depth.
Notable Point · 1:04:51-1:06:07
Japan captured more islands than its logistics could fortify
Japan's rapid expansion outran the naval, merchant, engineering, artillery, and armour resources needed to turn every island into an effective defensive position.