But there's a big thing going down between China and Japan right now over a few small islands.
The Chinese people I work with have been mentioning it from time to time. It's something like a non-military Chinese ship landed people on the islands to occupy them and the Japanese, who claim the islands, ended up arresting the captain of that boat.
My Chinese co-worker and I were discussing American foreign policy the other day and I mentioned about how China should stop maintaining North Korea since if SK were able to absorb the north to form a modern country, then I don't see how we could justify being there and in Japan, and getting some breathing room is probably what China'd want.
She made the point that the Chinese view is hyper-defensive 'because they've had many wars and much destruction in their country' and apparently they see a potentially united Korea as a big enough of a threat. China is still pretty sour at Japan.
Personally I think that's silly talk since SK is one of China's biggest trading partners and even an enhanced SK would be tiny in comparison, only 75 million people or so at present. Not to mention having an active economic land border has to be better for the border region than having an economic black hole on the other side, but perhaps they fear Korea would start spilling over into that region of China. On top of this, there are thousands of years of history and relations between the different groups in Asia that as non-Asians we're completely oblivious to.