Chinese will be looking at their own National Interest no ? right now Chinese Military Think Tanks might be evaluation all possible outcome of any Strikes against the N.Korean Regime .. N.Korean Situation remind me of Iranian Threats to US that they did not have Capability to Hit US but they threat to Obliterate Israel in case of any Offense from US which will turn the entire region upside Down.. Chinese will try not to get involved but if threatened they will do whatever they can to do some sort of Damage to US to weakened her and her Allies in Region dont you think so ???
the moment N.Korea hit by US strikes , they might use the WMD to halt any Ground invasion from S.Korea or US and without ground Invasion , i doubt KIM is going anywhere ..
No, I don't believe China will not be involved.
The problem lies in how you would plan an ground invasion of North Korea and how this will impact North Korea, China, South Korea and the United States.
The first question is North Korea nuclear capability, at this stage, it is still an infancy, the Nuke North Korea processes will be at WW2 level, and the rocket technology as well as deliver technology is not as complicated and advanced to Russia, China, US or even India and Pakistan, if North Korea ever launch nuke, US would intercept them with Ballistic Defence, there may be some that get thru but still since NK Nuclear Technology is not as advance as others, they can do more or less the same damage to what US did in WW2. At this stage, tactical nuke NK process and BMD US process would mean NK nuke cannot stop a full on invasion had US/SK has one, it would have been casualty, but there won't be that large as to be able to stop an invasion.
The second question is US Strike and Intelligence Capacity, US would have keeping tab on NK Launch vehicle, if push come to shove, US can launch sub base tactical nuclear missile and destroy most of NK force before NK launch.
The First Strike capability US Process would mean there is a good chance that NK would lose a quarter to half of what they process before they can use it. thus minimize the damage.
The third question is North Korean response, if a US/SK Invasion is coming, NK could have see that as a betrayal from China, they could launch nuke over to China. As Beijing is well within range of NK missile (Pyongyang to Beijing is only at 500 mile, 1/4 of Taepodong I range) , I think the Chinese will have that in mind.
The fourth question would be Chinese reaction to a strike, Chinese reaction would not be in favour NK, a war now with North Korea would mean China to Pitched with the US, that will damage Chinese Economy and Military development, would China choose North Korea over relationship with the United States? It wasn't in the 50s anymore when China don't care about anything but communism, today, it's the second biggest economy in the world and a War with the US would mean a war both Physical and Economical with all the world, and maybe Russia and North Korea would be standing by its side, both of which have no to low impact on world economy.
The fifth question is what would be the US response. US response will be swift, they will not start a war unless the US have all intel at hand and a detail plan with associated allies before a move, and when a war is eventually happen, US will not be deterred easily, well, not at the first few year anyway.
That is my analysis on the issue.