There is some puzzlement, typified by Praktike's post on Political Animal, as to why the Chinese are getting all worked up about the Japanese all of a sudden. If I may paraphrase his concern, World War II atrocities are so, well, 20th century, and an unworthy preoccupation for a gung ho, charging-in-to-the-future regional power.
Certainly, the Chinese government finds nationalist identity politics a useful outlet and unifying force in times of trouble. And the demonstrations no doubt enjoy the tacit approval and support of the Chinese government.
But there's more at work than vulgar atavism. And to believe that the Chinese government is whipping up these demonstrations just to distract attention from their domestic difficulties is to ignore current international conditions that are driving the protests.
Japan's recent decision to overtly identify "peace in the Taiwan Straits" as a joint security concern of Japan and the United States was a regional bombshell. It cannot be viewed as anything but a deliberate decision by Japanese Prime Minister Koizumi to align himself with the United States and endorse a policy of China containment.
China, like Israel, has always mightily resisted attempts to internationalize its territorial disputes. Acknowledgement that Taiwan's reunification is China's internal matter has always been a prerequisite for friendly bilateral relations between China and other countries.
Koizumi has decided to abandon a policy of accommodation which acknowledges China as a dominant East Asian power, and instead has chosen to confront China under the aegis of U.S. military power.
Perhaps he feels Japan has more to gain--such as U.S. backing for access to Russian oil at China's expense--by serving as America's ally in the Pacific and not a Chinese client.
But the Chinese are reminding him there's a price to be paid for siding against China in China's back yard.
The size and vehemence of the demonstrations reflect two realities. First, that the Chinese government believes that the threat of an American encirclement campaign abetted by Japan is real and immediate enough that it must be confronted promptly and resolutely. Second, that the U.S.-Japan axis offers much potential for the polarization and destabilization of East Asia.
The roots of the current China-Japan crisis are probably a lot closer to Bush administration strategic doctrine than Chinese domestic politics.
What happens next in Asia, and why, has more to do with us, our actions, and our omissions than we'd probably care to consider.