Japanese interservice rivalry and the neglected logistics base

Why did the Imperial Japanese Army and Navy treat each other as such serious rivals?

Competition for limited resources and a weak supporting industrial base made each service fear losing out; both also underinvested in the logistics their wider war required.

Older clan and institutional rivalries form part of the background, but scarce resources kept the competition bitter. Both services chased visible front-line weapons while Japan underbuilt supporting industry and infrastructure. With so little spare capacity, losing an allocation contest could leave a service with no useful substitute. That made bureaucratic defeat unusually costly and intensified the rivalry. IJA-IJN conflict therefore involved force structure and resource allocation alongside its cultural and factional roots.