"Limited conflict", you say? Well, then you should know that in the past 30 years, the most extreme action the countries in South and East Asia are willing to do is to

spray water at each other, any if that fails, bump each other with their boats. The Navy and the Air Force of these Asian countries have not intentionally killed a chicken since the 60's.

This is China spraying Vietnam.

And this is Japan spraying Taiwan.

In order to get "bumping advantage", the Vietnam navy got itself an icebreaker to jump in the ring with the Chinese. This must be the first time a tropical country goes out and buys an icebreaker! ("Russia-built Semen Chelyuskin (1965–1988; ex-Ledokol-8 (1965–1966); sold to Vietnam in 2013. source: List of icebreakers)

"Limited action" in Asia means nobody fires a shot. So I would give the advantage to Japan, since the one and only icebreaker from Japan is bigger than the one and only icebreaker from China. On the other hand, it's rumored that recently PLAN retired an old cutter, painted it white, and gave it to the Fishery Administration, who's going to put a giant water canon on it...