I played a two-player game as the Axis, and I entirely ignored China. I pulled out most of my troops and never attacked the Chinese, instead focusing on Russia and the UK in India.
China took everything, of course, and it became a real power, but since it couldn’t leave its territory, I was able to replace the lost IPCs with those from Russia and India.
The land war against China nets a lot of IPCs, but I feel like it’s too slow given how much trouble Japan has initially with getting units to the mainland.
In addition, taking Russian/British territory results in IPC denial and prevents the British from successfully building and holding an Indian IC.
Meanwhile, in another game (I’ve only played Anniversary twice), the Japanese player spent all his time hitting China, and it didn’t work out well for him since he never got to Russia soon enough. Although, to be fair, in that game the Axis neglected to take out hardly any Allied navy on the first turn.
So why ever try to take China when it can be (apparently) safely ignored?