The opium wars may have been in the 19th century but the WW1 reparations, Sino-Japanese wars, rape of Nanking, and general widespread attemps to carve territory

The opium wars may have been in the 19th century but the WW1 reparations, Sino-Japanese wars, rape of Nanking, and general widespread attemps to carve territory from China, especially Western approval of the Sino-Japanese sphere of influence, were all 20th century. Western powers supporting the violent partioning of China was the norm even in the 20th century (look at Churchill's comments on the matter).