WTF, North Korea?

This is mildly alarming:

North and South Korea exchanged artillery fire on Tuesday after dozens of shells fired from the North struck a South Korean island near the countries’ disputed maritime border, South Korean military officials said. Two South Korean soldiers were killed, 15 were wounded and three civilians were injured, said Kiyheon Kwon, an official at the Defense Ministry. The military went to “crisis status,” and fighter planes were put on alert but did not take off. South Korean artillery units returned fire after the North’s shells struck South Korea’s Yeonpyeong Island at 2:34 p.m., said Mr. Kwon, adding that the North also fired numerous rounds into the Yellow Sea. News reports said dozens of houses were on fire, and TV footage showed large plumes of black smoke spiraling from the island.

In and of itself, this would be unfortunate but not particularly indicative of a major increase in tensions or a shift in North Korean policy. Combined with the Cheonan incident, the revelation of the nuke facility, and a number of other small incidents, it’s somewhat disconcerting. My best guess is this: North Korea is taking behavioral cues from the increasingly tense security relationship between China on the one side and the US and Japan on the other side. The North Koreans may believe that these tensions open up a wider space for action because they reduce the chances of collaboration between China and the US. Pyongyang may also believe that Beijing tacitly approves the series of escalations. I have no idea regarding Beijing’s actual attitude; China normally regard North Korea as an embarrassment, but in this case they may appreciate that the DPRK has some utility.

But that’s just guesswork. Thoughts?

…see also Spencer, Sigger, and Stratfor.