It has been Japan's policy to deploy its coast guard vessels instead of warships to prevent its territorial conflict with China over the Diaoyutai islands (Diaoyu to China, Senkaku to Japan, which controls them), from escalating into a full-scale war. The deployment of the Haijing 2901, which is also the world's largest maritime patrol vessel with a greater displacement than the Arleigh Burke-class destroyers of the United States, will eventually challenge this policy since Japan's coast guard has no vessel that can counter it.
With its 76mm rapid-fire naval guns, two secondary turrets and two anti-aircraft machine guns, the Haijing 2901 can easily overpower any patrol boat. If Japan's coast guard cannot oppose China's now "routine" patrols around the disputed islands, it could eventually lose control of the territory. The next step, an inevitable escalation, would be to deploy the warships of the Japan Maritime Self-Defense Force.
Tokyo would then be accused by Beijing of provoking a war by deploying warships against a maritime patrol vessel, albeit one that is a warship in all but name.
In the skies above the islands, a total of 464 sorties were made by fighters of the Japan Air Self-Defense Force in 2014 to intercept Chinese aircraft after China declared an air defense identification zone covering the disputed islands at the end of 2013.
The China Coast Guard Haijing (CCG) 2901 undergoes sea trials in the East China Sea.