Japan is reacting to threats to its security by pushing toward a "normal" military. China won't like what it provoked.
China in particular has worried Japan for quite some time, as I posted more than 15 years ago:
Japan is reacting to potential threats from North Korea and China by bolstering their defenses and their alliance with America, as the annual report by Japan's Defense Agency makes clear[.]
Japan has the means to be a major military power:
A Japanese decision to build upon what is already a not-insignificant self-defense force will change the geopolitical reality of the Pacific. China is already confronted by the United States, operating at an extreme distance from its homeland. Washington can do this, but if Japan remains an ally, then the Japanese can assume an equal or even a leading role. The cost and risk of containing China would then decline for the United States. It would strengthen the informal Quad alliance, which comprises Australia, India, Japan and the United States. American control of the Western Pacific would depend on American guarantees but not a continual, large-scale presence.
Key to this is that the U.S. and Japan maintain their alliance. It endured since World War II as a relationship of unequals. Japan’s military will not surpass the American force, and the U.S. guarantees open global waterways. Japan would not have the ability to do that, and as a major exporter and an importer of raw materials, Japan relies on the U.S. global presence. Therefore, unlike before World War II, the U.S. and Japan share crucial interests within a relationship crafted over several generations. An alliance of the world’s largest and third-largest economies, in which Japan builds a significant military force as well as growing its economy, would redefine the balance of power in the Pacific with minimal danger of discord, at least for the foreseeable future.
Japan's more assertive attitude took time to be evident. And now we can see the return of Japanese naval aviation.
But how much will the Japanese people support? I imagine China's rulers will help subdue post-World War II pacifist attitudes, much as Putin shifted neutralist attitudes in Sweden and Finland to one favoring joining NATO.
NOTE: My most recent war coverage is here.
