Japan is expected to move toward a prospective battle area in the South or East China Sea, perhaps around Taiwan instead of through the narrow strait. British submarines can wait on likely approach routes because the direction of the Japanese sortie is comparatively predictable. Numerous destroyers use ASDIC to protect the Allied main force from Japanese boats at the same time. T-class submarines are described as ambush predators designed to fire large salvoes at an enemy battle fleet, with commerce raiding as a secondary concern. A successful attack near the Japanese coast or fleet exit routes could damage capital ships before the surface fleets meet. The approach to battle, intelligence about routes, and anti-submarine screening are therefore as important as the fleet action itself.
Notable Point · 48:10-50:00
Submarine ambushes before the fleet battle
Forward-positioned British submarines and destroyer anti-submarine work could make the South China Sea or waters near Taiwan a dangerous approach route for Japan.