@victoryfirst
The Japanese Strategy should mainly focus on China from Early 1940 to Early 1941.
During this period, the only naval units that Japan should produce are Transports.
These Transports should be moved in position for a Large Scale Offensive in the Pacific - following the American Declaration of War against Japan, Italy and Germany.
The Imperial Japanese Navy that exists from Early 1940 (game start) should mainly focus on the defense of the Japanese Homeland from Late 1941 as well as the coast line to Asia while protecting a small group of Transports that bring fighting troops to Asia.
From Early 1942 the Japanese Navy can be gradually expanded - in order to meet the threat from Allied Naval Task Forces.
If US troops land in Asia or Soviet Far East, it will be easier for Japan to eliminate them.
If the US troops - as well as ANZAC troops - capture the islands in the Pacific, it is much more difficult - and costly - for Japan to re-capture these islands.
Japanese occupied islands should be fortified - and Caroline Islands should be strengthened with a few Infantry units - and also have a few Fighter units to serve as the back bone of the defense.
One Fighter unit could even be used to scramble to prevent Naval Bombardment.
The Japanese Naval Base at Caroline Islands should be destroyed to prevent it from falling into enemy hands.