[WernherVonTrapp]

China was a primary objective for the Japanese. It's natural resource alone were enough to raise the eyebrows of even the staunchest (potential) objector to their mission there. That doesn't even consider the potential factory workers, slave labor, what have you, that they could bring to bear upon their war machine. There was no way they'd have overlooked China. The Japanese also, did in fact have their eyes on India but, by the time they took any initiative, they were already overextended on all fronts and could not sustain their momentum.