The suggestion is they are in dire straits, this is their last gamble, there have been coup attempts on Kim, and it is only a matter of time. They know "Iraq" is "target practice" for the DPRK. Convinced, in fact, of that inevitability. What's there to lose?
They have shifted nearly all of their national resources, and spartanly starved the poor people accordingly, into the military complex for offensive purposes.
Japan should have been allowed to restore order in Asia a long time ago. I'd imagine this is the last thing China wanted to happen.
Japan, Australia, South Korea, and Taiwan are not to be taken lightly.