Japan & SoKo are uneasy not just with NoKo, but the fact that major support NoKo gets from China & ruling Chinese Communist party. Without China support, NoKo oppressive regime of dear leader Kim will fall like a pack of card. China is the one sustaining & feeding the regime to keep SoKo and Japan at bay and keep US engaged in endless quagmire, else their attention will shift towards democaratic Taiwan's legitimate demand for independence. It all geopolitics. What China never realizes is that Japan eventhogh has taken an oath for never manufacturing a Nuclear weapon, they are very much capable since major Nuclear reactor components for electricity are made by Japan. They are technologically monopoly in reactor field. Their pacifist constitution is holding Japan back