[RobotToaster]

Tibet was part of China since the Quing dynasty in the 17th century, it briefly declared independence during the chaos of the Chinese civil wars, but it was never recognised.

Vietnam is usually recognised as a low point in Chinese history.

There's been an ongoing border dispute between China and India for over 100 years, thanks to some questionable line drawing by the British.

Also, referring to the parent comment, of these only the border skirmish with India was within my lifetime.