What Are They Thinking?

I just saw on Drudge the link for this story from the Washington Free Beacon that China has mobilized troops near the Korean peninsula. From the story:

China has placed military forces on heightened alert in the northeastern part of the country as tensions mount on the Korean peninsula following recent threats by Pyongyang to attack, U.S. officials said.
Reports from the region reveal the Chinese People’s Liberation Army (PLA) recently increased its military posture in response to the heightened tensions, specifically North Korea’s declaration of a “state of war” and threats to conduct missile attacks against the United States and South Korea.
According to the officials, the PLA has stepped up military mobilization in the border region with North Korea since mid-March, including troop movements and warplane activity.
China’s navy also conducted live-firing naval drills by warships in the Yellow Sea that were set to end Monday near the Korean peninsula, in apparent support of North Korea, which was angered by ongoing U.S.-South Korean military drills that are set to continue throughout April.

Is China stuck in 1950? There is a truism that armies always prepare to fight the last war. For China, the last major conflict they were involved in was the Korean War, and it sounds like they are planning in fighting it again. The question is why? What interests do they really have in supporting North Korea? I would suggest that they have no reason for supporting North Korea militarily. However, they have plenty of reason to fortify their border from a mass exodus of North Koreans should the North Korean regime collapse. They may also be beating their war drums to achieve some gain over the South China Sea should conflict break out.