Nagano chose war and threatened resignation when Yamamoto's operational demands were resisted. Yet he did not ensure rigorous war-gaming of the operations he approved. Japanese attention to submarine warfare developed too slowly, and the navy lacked a durable personnel and pilot-replacement pipeline. Both Nagano and Yamamoto warned that the conflict would be long. Their failure to prepare the systems needed for that prediction is therefore a command failure rather than an unforeseeable wartime surprise.
Notable Point · 2:15:49-2:17:00
Nagano recognized a long war but did not prepare for it
Nagano's responsibility lay in supporting war without imposing rigorous war games, faster submarine preparation, or replacement systems suited to the long conflict he anticipated.