I think china should have let the north korean communists get whiped out when they were originally getting their arse kicked, but, we have to remember this was a different time, it was the cold war and china was extremely communist, it wasnt going to allow a rising communist neighbour get crushed by the invading amerikans.
It seems at one time each durring the war the north koreans were on the verge of being whiped out, and then the south koreans + allies.
I think china has progressed enough that, as gs001 has shown, the chinese may be regretting their part of the korean war, and its nice to know at least someone is questioning the almost insane amount of hostility and demands on japan, but china still deserves its war apology (aslong as it can see fit to forgive before hand) and as for chinas involvement in the korean war.....sad but, it was just an act of the times, when it was communism Vs Democracy, it was a crappy world and yeah, hard times had by all.
I dont think theres any doubt the continued growth of chinas prosperity will eventually lead to a fully free and democratic china, despite its slow crawl, so china cant be considored as communist as it once was, it seems north korea is the last remenant of an old dead and un-needed philosophy.
Communism grows from the anarchy of wars and strife and poverty, but, when things start getting good again, its soon seen to be more of a burden then a blessing, and is discarded.
The day will come when china no longer needs it.