Marine defense forces lacked the artillery, anti-aircraft weapons, and construction support needed to create strategic depth on isolated bases. If construction battalions could transform islands quickly and arm them heavily, Japanese forces returning after only a short interval might face a position far stronger than the one they had reconnoitered. Each attack would then demand more than a light raiding force or a few cruisers. Requiring repeated commitment of battleships and other heavy units could overwork the Imperial Japanese Navy and complicate its operational tempo. The proposal treats island fortification as a way to impose fleet-level costs rather than merely hold ground.
Notable Point · 41:44-43:06
Using fortified islands to strain Japan's battle fleet
Rapidly fortified island bases could force Japan to commit battleships and heavy guns repeatedly, imposing operational strain.