The Republic of China (ROC, often known simply as "Taiwan") and the People's Republic of China (PRC) both claim to be the sole legitimate government of all of China. But the two polities have different notions of what "all of China" means in geographical terms.
There is clearly a great deal of territory that the ROC considers, or once considered, to be part of China that the PRC does not. (For instance, until about 20 years ago, the ROC considered the entirety of Mongolia to be its own territory.) But conversely, are there any territories that the PRC does claim to be part of China that the ROC does not claim to be part of China? If so, what are they?