When you screw with another communist dictator your life gets very interesting, and usually rather short.
Good point and an interesting concept.
China could absolutely own Bambi and the Euroweenies by swatting the annoying NoKo biting fly. It could be the watershed event that solidly cements their status as the newest and soon-to-be most powerful superpower — economically, militarily, and diplomatically.
For starters, there is the Korean Autonomous region of Yan bian which lies within China's borders and shares a border with NK. The population (2.1 million) is over 95% ethnic Korean. A Korean peninsula war would send millions of impoverished refugees north across the Yalu and into China by way of Yan bian.
Not to mention it’d be a quick and effective way for China to spend some of that huge mountain of dollars it’s accumulated over the years.