My few cents- There is a very slim possibility of both: neither North Korea attacks South Korea or Japan nor US attacks North Korea till China is there. The current voices of China are just to make friendships with the countries which have in fact helped to bust its economy. China has not feared with nuclear North Korea but South Korea and Japan have. Shinzo Abe has feared the most, because of its historically bad relationship with the north. Even if US plans to attack NK, China will not just wait and see where US interests are circling its territories. Kim Jung Il has carefully analyzed the situation. The current situation goes like this: China will eventually show its softer stands towards NK and the status quo with rounds and rounds of talks will be held. At the same time, the countries like Iran will go ahead with their nuclear programs. US has got a good lessons from Iraq and Afghanistan and can do nothing with Iran. It will just try its failed foreign policies to make more number of supports with no real gain. It is unlikely that China will sideline with Japan as Isolated_Freek assume. Historical relationships and the Koizumi's Yasukuni shrine are enough to say so. Japan has scared with China because of China's economic growth and economic forecasts of being superpower in future. If there is a war, it starts between American bases in Japan/South Korea and the NK. However neither NK starts first nor the US. There are few reasons NK is doing its current business: It fears of US attracts thorough bases in Japan and South Korea, it wants to show communist strength to US for its hates towards communists, leaderships fear of unseat by US sponsorship and it wants to blackmail for food and necessaries with nuclear programs to uplift its starving population. Unless American bases in Japan and South Korea will not be removed, such situation remains and north will play.