A viewer cites a Japanese study estimating that invading Australia would require ten infantry divisions. The estimate supports the larger conclusion that Japan lacked the forces needed to carry out such a conquest. Japan could threaten, raid, and posture against Australia without possessing an available force for a successful continental invasion. The distinction matters when assessing Sydney's danger: the fleet base could be attacked without making occupation of Australia a realistic objective.
Notable Point · 2:33:28-2:33:55
Why Japan could threaten Australia but not conquer it
A Japanese estimate required roughly ten infantry divisions for an invasion of Australia, a force the country did not have available.