That's big if China threatened to cut off their oil supplies but if so it worked.
I have no idea as to the track record of that paper or the accuracy of the story. It does say the cut happened in Sept. That thread crosslinks to a similar story translated by TigerLikesRooster, here: China Cut Oil Shipment to N. Korea (and invites Chia Head for a talk)
So it isn't the immediate cause-and-effect that the posting sequence seems to indicate (as I erroneously implied), but rather the result over time of sanctions kept up.
I'm certain that without China's help, we didn't stand a puppy's chance in Pyongyang of bringing this about on our own. Unrelenting pressure by the regional powers is the key. Bush understands this, the democRATs don't have a freaking clue. The RATs will get us all killed.