When I see North Korea launch a major artillery attack on South Korea with a building pattern of aggression, my first thought is what the hell are they thinking? They can't possibly want to re-ignite the Korean war, which is technically still a war (cease fire, no peace agreement). Yet at the same time the leadership there is borderline insane, and I doubt it would take more than a puppet show to convince them that they could win another major conflict against an Asian Tiger (supported militarily by the USA).
It would seem that the most likely scenario is that North Korea is using a show of force in an attempt to scare the international community into a better extortion deal. The question is, how much more should South Korea be expected to endure in order to secure a "golden parachute" for Kim Jong Ill?
What's China saying? Only Beijing has sway over Pyongyang.