Everyone's a bit troubled by Kim Jong Il's decision to test a nuclear weapon. The South Koreans are unsurprisingly worried. The Japanese might get back in the military game after a sixty year absence.
According to Dan Drezner, the Chinese are pissed, possibly because of the last-noted prospect.
I know nothing, of course, but it seems plausible to me that the Chinese government has a few friends around the Central Committee table with ambitions of starting their own Leninist-jucheist dynasty of Communist tyrants. If China is annoyed enough, I figure Kim Jong Il may be sleeping with the fishes.