Where To Worry About China?

China's military is probably more of a threat to Filipino fishermen and merchant ships in the East China Sea than to Taiwan, which it would face far more severe consequences for invading than it would in an insidious, low intensity campaign to gain de facto control of waters that belong to other countries or are international waters.

China has the military might to launch a land invasion of North Korea, for which the world would thank it (even, eventually, the liberated North Koreans). Russia or Mongolia or Kazakhstan would be very angry but not very weakened by losing a lot of land with few people on it, and would receive little international support to defend themselves. An attempted land invasion of India would yield mostly uninhabited frigid mountains that have never been exploited for their mineral resources, at a high cost.

China has no need to invade Laos or Vietnam, which are already in its sphere of influence. It has no reason to invade the other "stans" on or near its border or Burma, which would be more trouble than they would be worth.

Invasions of South Korea or Japan would be too costly for it to attempt, not just militarily, but in the collapse of the international trade based economy upon which it relies for its prosperity.