Japan Determines Intruder Sub is Chinese SSN

This article from CNN is among the many on the wires today announcing Japanese plans to file a protest with China after determining the submarine that had entered Japanese territorial waters near Okinawa was a Chinese nuclear sub. If true, this was almost certainly a Han-class SSN, since I consider it very unlikely that the Chinese Xia-class SSBN would go that close to any other country. The reported presence of the submarine rescue ship and towing ship that the submarine was heading towards supports my earlier contention that the Chinese sub suffered some sort of mechanical breakdown that limited its' ability to evade ASW forces.