If I may add, the growing naval cooperation between Japan, The United States, and Australia -- in the Pacific Ocean Region will be a factor in preventing any Chinese foolhardly decision to instigate anything. When it comes to maritime brinksmanship, Japan is not afraid to stand up to adversary (we have fought far more larger empires than us in the past -- ergo, The Russian Empire, The United States --- and have not back down to a fight even when the odds were against us). The fact that Japan (which has a legacy of not backing down to a fight and with a mature and formidable naval force) has a strong all-weather security alliance with the Untied States (the world's greatest power) means that any instigation and conflict would result in an immediate response , an overwhelming one at that, by both the United States and Japan.
Conflict should be a foregone conclusion, however, we are not afraid to unsheath the proverbial Katana when we have to. Japan , by her very nature, is a martial power. We have never, in our history, backed down from any adversary. Not to the Chinese, the Mongols, Russians, Americans, et cetera. The United States, too, has an unmatched naval legacy , not to mention shear military power.
I think these factors should be enough to send a dose of reality to any would be agitator.
We can count on one hand the militaries that actually 'took on' the US, whether by choice or by circumstance:
- Germany
- Japan
- China
- Iraq
China is unique in that China 'took on' the US twice, or thrice, depending on perspective:
- Direct confrontation in Korea.
- Second hand in Viet Nam.
- Rhetorical in the world.
This history is neither ignored nor forgotten by the leaderships of both countries. The lessons of Korea gave pause to what China is willing to bear in Viet Nam when Ho Chi Minh sent a delegation to China to appeal for active combat participation in the manner of US forces, the result was that China relegated her forces to support roles to the (North) Vietnamese.
China cannot fight US on the rhetorical battleground the way she did during the Cold War simply because today there are too many types of relationships between China and the US, prominent of those relationships is economic. China does not have any ideological conviction to support any proxy in that proxy's conflict against US --
vis a vis Viet Nam.
That leave direct military confrontation.
Despite being a continental power, China's coastline made her a sea power as well, or at least a potential one. Unfortunately, China have let that potential atrophied to the point of gross negligence. Not so with Japan. Despite the devastation of WW II, Japan's reconstruction of every aspects of her society have not ignored the sea power potential the way China did and that mindfulness is reflected in the JMSDF today. Absent a large land army to support territorial expansionist goals, that leave the JMSDF the primary, if not sole, executor/protector of Japan's national interests outside her islands. Keep in mind that throughout history, first impressions of countries are usually made by and between military commanders before the self importance diplomats takes over. So if Chinese aggression continues to build, and I believe it will, the JMSDF will have to don the 'diplomat' hat as well in trying to build an alliance of Asian countries to counter-balance China.
Despite the childish 'nuking', the DF-21D, and DSI blather from the Chinese camp on this forum, China cannot afford a direct military confrontation against the US. That leave US Asian allies vulnerable to Chinese bullying and this is where Japan, via the JMSDF, can take the lead, even ahead of the US, in securing an Asian alliance to counter China. South Korea, unfortunately, will not be of much help simply because of constant vigilance of North Korea. South Korea can, at best, protect her territorial waters, and not able to protect Japan's flank in the East China Sea, that leave -- again -- the JMSDF.
The boldest move the JMSDF can make -- and this will take diplomatic and military balls of brass -- is a direct run to Viet Nam and secure at least an initial first impression of good will between the two countries. Currently, the PLAN is too weak to directly confront the JMSDF, even without US support, but with US support, a relationship between Japan and Viet Nam will reinforce the belief that freedom of navigation in the South China Sea is necessary if these smaller Asian countries are to economically prosper.
Japan is in a tight spot, for the historical long term, and all three major powers knows it.
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bad-*** .... 
