Some Chinese have made noise that Okinawa belongs to China as well. The Chinese government hasn't said that yet, but given China's tendency to expand, pause, expand, pause, expand and so on I expect that if they do get the Senkakus they will eventually start pressing a claim on Okinawa as well. Given that Japan itself managed to repel Kublai Khan's invasion efforts China probably won't ever claim Japan itself, though they might justify attacking Japan based on Japanese actions in WWII.