Russia has deployed K-300P bastion missiles on Kuril Islands.

http://www.bestchinanews.com/Military/7271.html

It was reported that Russia deployed K-300P bastion missiles on the Kuril Islands after Japan received its first F35 fighter plane.  This type of missile can fly at 2.5mach and the missile system will usually fire 2 missiles at around the same time.  Once one missile hits the target, the other missile will search for the next target.

Kuril islands are very near to Hokkaido and these bastion missiles will definitely put Japan on constant alert.