The most likely explanation is that China is considering some action in North Korea. The Koguryo southern border roughly matched the present-day boundary between the prosperous South and impoverished North. Over the past few years the Chinese have done much to increase their economic presence in North Korea. It seems that the collapse of North Korea is not something the Chinese would be happy about. The growing likelihood of an emergence of a unified and democratic, perhaps pro-US Korea just across the border from China is not particularly good news for Beijing strategists.
Hence Beijing seems to be preparing some contingency plans for a major domestic crisis in North Korea. These plans might include an installation of a pro-Chinese puppet regime in Pyongyang and perhaps will require involvement of Chinese civilian and even military personnel (ostensibly on a humanitarian mission, as distributors of aid and maintainers of order, actually as supporters of a future post-Kim regime). Such actions will require psychological and cultural justifications, not least within China itself. Thus presenting what is now North Korea as an "ancient" and "integral" part of China might serve such interests very well.asisa times
China shows its willingness.
The South Korean leader also talked about history issues with Japan, the "ripple effects" of Japanese politicians' visits to the Yasukuni Shrine that honors war criminals, but said he was not as concerned about the more recent history issues raised with China's "Northeast Asia Project," according to Gregg.yonhap2006/09/16 05:57 KS
South Korea show the willing to getteing closer to China.
South Korea feels irresistable towards North Korean women.
How about USA's move?