Here is a very good post on the state of what's going on in the region of the Pacfic Ocean where China, the Korean peninsula, and Japan meets. Specifically, the Senkaku Islands where China, Japan, and Taiwan all claim sovereignty over.
China has allowed the North Koreans to run amok while itself has becoming increasingly belligerent towards its neighbors. Case in point. Despite improving relations between its semi-independent island province of Taiwan, it still has hundreds of missiles pointed at it. And more recently, a Chinese warship locked weapons radar on a Japanese defense ship.
So now, Japan is looking beyond the restrictions imposed upon it by its pacifist constitution and turning its self-defense force into more of a regular military that any other nations might have.
And with the US obligated to come to the aid of its friend, which may include Taiwan, don’t think a few hawks in the US government aren’t looking to knock China down a couple of steps by simply targeting China’s military infrastructure in a limited engagement.
So now, Japan has to worry about both North Korea and China's juvenile behaviors.
Just saying…Beijing, boneheaded moves, dude…
Note: Not to mention the hacking by the Chinese military.
Another Note: For those who would protest that Taiwan in a country, puleazeeee...Taiwan's