Like I've said before, this is the New Normal.
Japanese fighters have intercepted two Xi'an H-6G bombers and a similar number of Shaanxi Y-8J AEW/MPAs [.pdf] belonging to the Chinese Navy transiting through international airspace over the Miyako Straits on their way to the Western Pacific on Friday. The two H-6s were flying together, while the Y-8Js flew singly, at different times of the day. The above graphic illustrates the tracks of the individual aircraft.
The Chinese aircraft would likely have been involved in a massive exercise involving all three fleets of the Chinese Navy. The Chinese have also said that the exercises were monitored by "foreign military vessels and reconnaissance aircraft".