I wish Japan were allowed to man up and build up their defense and a Nuclear arsenal, that should put the scare into North Korea, China, and Russia... a strong Japan.
Japan is not a nuclear power only because they choose not to be. I believe they have the information and the technical capability to create nuclear weapons. If the NKs launch a nuke figure Japan will probably successfully intercept it, a couple of months later several NK military installations disappear from aircraft delivered weapons.