Yes, I know that Japan is buying V-22s (but China may think they have an answer to that) and building a small marine corps with amphibious assets to beat China to occupy the Senkaku Islands (which China claims to own, too) in a crisis.
But since China will initiate any such race, China will have the advantage in timing the race while Japan is unready (perhaps because of weather alone).
Consider that China has naval assets capable of moving fast:
Zubr is a 555 ton watercraft developed by the Soviet Union during the 1980s. ...
The Zubrs can carry about 150 tons of cargo, including tanks (three of them). Alternately, ten smaller armored vehicles can be carried, or trucks, or up to 500 troops. The big advantage of the Zubr is that it moves over coastal waters at speeds of up to 110 kilometers an hour (nearly a hundred kilometers an hour sustained.) Range is short (about 480 kilometers), mainly because a craft like this consumes enormous quantities of fuel. ...
Zubrs are also seen as key weapons if China decides to settle some disputes with its neighbors over possession of contested islands. Using the Zubrs, with air cover, China can occupy disputed islands, even those with small garrisons, before anyone can interfere and then offer to make peace.
China plans to have 8 by next year with up to 5 operational, at first. That's a significant payload capacity for small islands that can't hold much, anyway.
China is certainly making belligerent noises:
Over the last several months, Chinese leader Xi Jinping and the Chinese Communist Party have repeatedly exhorted the People's Liberation Army to "be ready to win a war." Xi has repeatedly called for greater military modernization, increased training, and enhanced overall readiness of the Chinese army, navy, and air force.
Certainly, part of this motivated by a desire to make the Chinese personnel match the new quality of their weapons. Shiny weapons are just expensive soon-to-be-junk if used by poor quality troops led by corrupt officers.
But even is Xi isn't telegraphing imminent war, making the military better does in fact make them "ready to win a war." Perhaps a war with Japan.
China is edging their starting position closer to Japan's largely undefended islands by building a large base:
Several landing strips have been paved on the main Nanji island, Kyodo reported. The islands are about 100 kilometers closer to the disputed territory than the main island of Okinawa[.]
I think that counting on racing China to the islands ignores the history of these disputes that whoever occupies these islands in force pretty much gets to keep them. No matter what the legalities are, attacking is a viewed as a bigger breach of the peace than defending.
China is not shy about building up their forces in disputed islands, after all.
Honestly, if China makes a move on any single country, others should move to fortify their claims while China is busy.
Japan should occupy the islands. As a first step to manned outposts, perhaps Japan could send in the robots to defend the islands.
Or will Japan really use their new marine corps to assault and retake the Senkakus when China makes their move to take them?
Then the war gets bigger.
Is Japan counting on Chinese rhetoric on war being something other countries need to worry about?