AAP40 Rulebook
Page 8
The Political Situation
Third paragraph from the bottom -
“The U.S. cannot attack Japan, disrupt Japanese convoys, or move units into China until Japan provokes war with the U.S. (see above) or the U.S. declares war on Japan, whichever comes first. If the U.S. is not yet at war with Japan by the Collect Income phase of its third turn, it will declare war on Japan at that time.
When the U.S. enters a state of war with Japan, whether due to Japanese aggression or its own declaration, its income is immediately increased by 40 IPCs (bring it to 50 IPCs) to reflect its wartime economy. It can then attack Japan in its next Combat Move phase.”
Page 10
Order of Play
#1. Japan
#2 United States
Page 10
Turn Sequence
#2. Combat Move
#6. Collect Income
If Japan does not do an Allied attack on J3, then on US3; the US may not attack Japan.
This delays a US attack on Japan until US4.