I believe the threat Trump made towards North Korea, was 100% a message to China. There is another level to this chess match that most people do not understand. Simultaneous to his statement, a blockade and military buildup was not reported on the borders of NK, it was in fact an ally of the USA, India that began taking up a position on a Chinese border, and a US warship the USS John McCain (destroyer) slips into the south China sea.