The Japanese Defense Ministry has drawn up a list of potential sites for its Aegis Ashore missile defense systems.
By Commander, U.S. Naval Forces Europe-Africa/U.S. 6th Fleet (Aegis Ashore Missile Defense Complex Romania) [Public domain], via Wikimedia Commons
They are Kamo sub-base in Oga, Akita Prefecture, and the Sado sub-base in Sado, Niigata Prefecture for the eastern coast site and Unishima sub-base in Tsushima, Nagasaki Prefecture, and the Fukuejima sub-base in Goto, Nagasaki Prefecture for the west.