ORIGINAL: Elessar2
Chinese Belligerence vs. Japan needed to be toggled on. Huh. Yes, I am sufficiently aware of the binary nature of the codes for such apps, but my assumption was that if they could attack each other they were belligerent by definition.
There are some cases in game where we allow nations not belligerent with each other to attack each other in order to prevent possible gamey moves.
For example, if let's say India had units in China, as they are allied together, but India is not yet at war with Japan, an Allied player could use Indian units to block Japan from attacking or capturing hexes in China etc.