Nationalist Chinese income question

[AxisAndAllies1940]

In 1936, Nationalist China starts with 6 IPCs of income. Now if the Communists take, say, Sichuan (worth 2), does the Nationalist income go down to 4, or do they collect all income possible minus the 2 (so 8 per turn)?

Thanks

[Mountaineer]

They collect separately. Even after the truce, they are separate countries and collect separately.