The fact is, China builds its own front-line fighters. Period....! That gives it greater autonomy to experiment and produce as many as they want, and produce them in incremental or evolutionary technological advancements, to be equipped with the best technologies and Industrial production capability available to the Chinese Nation. Japan can buy all it wants, but China will from now onward always have the advantage.
You can try to project and beat the drum all you want for Japanese and South Korean warplanes in a 'China Flanker Thread', but it ain't gonna convince us that Japan and South Korean planes bought from a foreign country is going to give them an edge over China,not when you consider the whole war-fighting systems , Military Industrial complex and Industrial capacity already in place. Nope, sorry.