The editor of a Chinese trade magazine sipped her tea one afternoon several years ago in a Shanghai tea shop and said: "I think Taiwan should be part of China but I don't think it's worth fighting over." She went on: "But if we give up Taiwan, then Tibet will try to break away and we will have separatists among the Uyghurs in western China and among the Mongols in Inner Mongolia and the Koreans in Manchuria."

She lamented: "If we let them all go, what will happen to my country?"

That editor's anxiety reflected a deep fear among educated Chinese who are keenly aware of the expansions and contractions of China throughout history. It underlies the deep fear of Chinese leaders caused by today's uprising of Tibetans in Tibet and in southwestern China.

In turn, that explains the ruthless and often brutal Chinese suppression of dissent in Tibet and everywhere else. It is more than just the leaders of the Communist Party afraid of the challenge to their authority and legitimacy.

Among those seeking to cast off Chinese rule are different objectives. Some Tibetans want autonomy within China to practice their Buddhist religion and preserve their culture. Others want independence. On the self-governing island of Taiwan, many people seek independence, many others want the nebulous status quo to continue, and a small number want to join China.

Chinese leaders, however, lump all dissenters as separatists or "splittists." The executive director of the political activist group Human Rights in China, Sharon Rom, said this month: "Too often the cultural and religious expressions of Mongols, Tibetans, Uyghurs, and other minorities are labeled by Chinese authorities as separatism or terrorism. In this system, it is not surprising that tensions boil over."

Of the 1.3 billion people in China, less than 10 percent belong to one or another of about 55 minorities. They range from the Zhuang, with about 15.5 million in southern China, to a clan of 2,300 Lhoba in southeastern Tibet. The vast majority are Han Chinese who take their name from the Han Dynasty that ruled a unified China from 202 B.C. to A.D. 220.

Although small in number, several minorities are closely watched by the authorities in Beijing because of their strategic locations on the borders of China. Tibet sits astride the Himalayan mountain passes into Nepal and India.

The Uyghurs, along with a smattering of Kazakhs, Kirgiz, Tajiks, Uzbeks and other Turkic people who are Muslims, live in western China next to the nations of Central Asia. Some want to set up independent nations; others want to join with Central Asian nations of the same ethnic groups that became independent after the breakup of the Soviet Union in 1991.

Beijing ordered the arrest this week of supposed leaders of the East Turkistan Islamic Movement for allegedly plotting violence to disrupt the Olympic games scheduled for August in Beijing.

Of the 24 million people in Inner Mongolia, which borders on Mongolia and Russia, only 10 percent are Mongols. Shortly after they came to power in 1949, the communist government in Beijing flooded that autonomous region with Han Chinese immigrants. That was the same tactic to which Tibetans object today.

In Mongolia, with a population of 2.8 million, there is little sentiment for reunion with Inner Mongolia. A Mongol official explained: "There are more Han Chinese in Inner Mongolia than there are Mongols in both Mongolia and Inner Mongolia. If we were united, the Han Chinese would take over our country."

Koreans, who number 2 million north of the Yalu River in what was once Manchuria, have been immigrating into northeastern China for several centuries. Most recently that was encouraged by Japan when the Japanese occupied both Korea and Manchuria before World War II. Because starvation is widespread in North Korea today, Koreans are fleeing into China to survive.

Some of those Koreans contend that their neighborhood should be incorporated into North Korea; that sentiment may grow if North and South Korea, divided after World War II, are reunited. In the opposite direction, scholars at the Chinese Academy of Social Science have recently claimed that North Korea, known in ancient times as Kogoryo, belongs to China.

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia. His column appears weekly in Sunday's Focus section.