Maybe the Senkaku islands have something to do with this?
The thought had occurred to me that the Korea mess could be a useful diversion to take attention away from China's adventures in the South China Sea. Might that possibility encourage China at the last moment to march in and stomp on the fingers of the Kim Regime as it is about to push the nuke button? China would certainly get praise internationally for doing so, and it seems possible. However, it's still just a poorly formed thought and I don't know what might be in the heads of any of them.
I am concerned that the powers-that-be in the United States may not have substantially more hard information, and that's very worrisome.