Recently, an article appeared in a Chinese magazine describing the beginning of the Korean war, sixty years earlier. What was unusual about the article, in a government approved publication, was the frank admission that North Korea had started it all, by invading South Korea. But once news of the article spread, and was posted on Internet sites, the Chinese government ordered the article withdrawn, and denounced it as untrue. The unofficial reason was that China wished to avoid angering North Korea. This, despite the fact that Chinese participation in the war killed or wounded over half a million Chinese. Even Chinese leader Mao Tedong lost a son in Korea.
Since 1950, it had been the official Chinese position that the war started with a South Korean invasion of the north, to which the north responded by moving into South Korea. For decades, all communist nations accepted this version, even though all evidence pointed towards the north invading first. Then, in the 1990s, the Russian government released telegrams sent before 1960, by Russian and North Korean leaders, making it clear that Russia wanted the invasion, and that North Korea duly carried it out.
Chinese troops entered North Korea in late 1950, to prevent American forces from occupying all of Korea, and that resulted in a three year stalemate along the current inter-Korean border (the DMZ, or Demilitarized Zone). Over 200,000 Chinese died in the war, in addition to half a million North Koreans, two million South Koreans and 37,000 UN troops (over 90 percent of them American). To justify the losses, and maintain good relations with North Korea, China continued to insist that South Korea had started the war, even after everyone agreed that Russian leader Josef Stalin and North Korea had been the instigators.
What this incident really tells North Korea is that China has admitted the truth about who started the war (by authorizing the article's publication in the first place), but is so sorry for this accident and officially sticks by the earlier lie.