China's main concern with Kyrgyzstan centers on China's own large and restive Muslim Turkic Uyghur minority, which lives primarily in the Xinjiang Uyghur Autonomous Region. That province makes up one-sixth of China's territory and borders on seven countries, including Kyrgyzstan, where the frontier is largely mountainous.
Five decades of Chinese Communist colonization policies have raised the ethnic Chinese, or Han, share of Xinjiang's population from 5 percent to some 40 percent, and about 1 million Chinese troops are stationed there.
Xinjiang is historically closer to Central Asia than to the centers of Chinese power in eastern China. Beijing tenuously controlled it as part of its land empire for only about 100 years in the 18th and 19th centuries, and Chinese influence waned following revolts in the 1860s until the Communists came to power in 1949.
The closing of the border trading station at Irkeshtam -- where Uyghurs live on both sides of the frontier -- at peak trading season is probably intended as a warning to the Uyghurs and the new authorities in Kyrgyzstan that Beijing will protect its interests.
Xinjiang has a long history of political restiveness toward what many Uyghurs regard as Chinese colonial rule, and most experts point out that strong tensions are never far beneath the surface. U.S. China expert Gordon G. Chang wrote that "violence flares in Xinjiang almost daily."
Reinforcing the problem is a deep and mutual feeling of cultural alienation. This expresses itself not only in language and religion but even in diet, where the Han Chinese fondness for pork as their staple meat is repugnant to the Muslim Uyghurs.
The two communities live next to rather than with each other, and Australian-American sinologist Ross Terrill has described government policies as producing "apartheid with Chinese characteristics."
There is little hard and fast information as to the extent of organized opposition to Chinese rule within Xinjiang, but Beijing has repeatedly made it clear that it will not tolerate any political interference from abroad, where pro-independence Uyghur organizations exist. Uyghur separatists accuse the ruling Chinese of political, religious, and cultural repression.
The collapse of the Soviet Union in 1991 triggered fears in Beijing of its possible effect on China's non-Han frontier populations, and the post-Soviet Central Asian governments have generally tread lightly where Chinese sensitivities are concerned.
Beijing is as worried about "splittism" in Xinjiang as it is about "splittism" in neighboring Tibet or "separatism" in Taiwan. The closing of the border trading station at Irkeshtam -- where Uyghurs live on both sides of the frontier -- at peak trading season is probably intended as a warning to the Uyghurs and the new authorities in Kyrgyzstan that Beijing will protect its interests. The politically motivated opening or closing of trading stations is a centuries-old tool of Chinese diplomacy.