Japanese planning increasingly centred on the US Navy from the mid-1930s without ignoring Britain as a major threat. Japanese leaders hoped that a European conflict would keep much of the Royal Navy occupied in the Atlantic and Mediterranean. That expectation was partly justified because Britain faced severe commitments in both theatres. It was not complete protection, however, because the Royal Navy still assembled and deployed an Eastern Fleet.
Notable Point · 1:49:13-1:49:46
Japanese planning for a Royal Navy tied down in Europe
Japan expected a European war to absorb British strength in the Atlantic and Mediterranean, reducing the force available for the Far East.