North Korea's official Korean Central News Agency announced the test took place Monday morning local time and seismic activity consistent with a nuclear explosion was detected by geologists in both South Korea and Australia. It occurred in the northeast of the country near the town of Kilju, an area that had been under U.S. surveillance as a possible test site because of the excavation of several deep tunnels there.

North Korea warned China that it was about to test and the Chinese passed the information on to the U.S. Embassy in Beijing. President Bush was informed Sunday night shortly before the test took place.

North Korea has kept analysts of East Asian affairs working overtime during the past few months trying to fathom the motives first of the test launch of seven missiles on July 4, and now of a nuclear test. Whatever the intent of North Korea's leader, Kim Jong Il, behind these displays of destructive capacity, they represent an extreme gamble by him on the patience of China.

North Korea is an economic basket case underwritten by Chinese food and energy aid. This is ironic as the country's governing ideology is still "juche," roughly translated as "self-reliance," developed by Kim's father Kim Il Sung, North Korea's founding president known as the Great Leader. North Korea's economy outperformed that of South Korea, measured by per capita GDP, until the mid-1970s. Today, however, South Korean economists estimate that their country's GDP is around 40 times that of its northern neighbor.

If China were ever to pull the plug on its flow of aid to North Korea it would precipitate a crisis. North Korea is counting that China will never do that and it is not in China's interests to do so. China's policy toward the Korean peninsula has two goals: the peninsula should be nuclear free, and stable.

Stability, for the Chinese, means maintaining the status quo including sustaining the Kim regime in the north. They see North Korea as a desirable buffer between them and a South Korea allied with the U.S. superpower and with U.S. troops on its territory. A collapse of government in North Korea would create a potential flashpoint as China and South Korea competed over cleaning up the mess with different ends in mind. China does not share South Korea's goal of ultimate Korean reunification.

North Korea's development and now testing of nuclear weapons challenges China's policy and faces its leaders with some tough choices that they would rather not have to make. China is not interested in foreign adventures at the moment. The priority is to grow the economy while maintaining social stability, particularly by creating the huge number of jobs needed to spread the new wealth.

For that China needs stability in its foreign relations, particularly in the East Asia region. North Korea's activities jeopardize that policy by forcing China to prioritize its two goals for the Korean peninsula. Will it continue to maintain the Kim regime at the cost of accepting it as an openly declared nuclear weapon state? Or will it pressure Kim to lose the nukes even at the risk of undermining his regime?

A nuclear North Korea poses a threat to the regional stability China is also anxious to maintain. Despite denials from aides to Prime Minister Abe that Japan has any intention of developing its own nuclear weapon in response to North Korea's test, this question is bound to become an issue in Japanese politics if North Korea does not abandon its nuclear program. A Japanese nuclear weapon would likely lead to a South Korean weapon, and either development would be very bad news from a Chinese point of view.

The Chinese are increasingly frustrated that Kim is forcing such unpleasant choices upon them and it is beginning to show. Kim ignored China's warnings against the missile tests of July 4 and the North Koreans refused to receive the diplomat dispatched by Beijing after the launch. China responded by supporting U.N. Security Council sanctions against the sale of any missile technology to North Korea. This was a first for China even though they modified a much tougher resolution initially proposed by Japan.

China's response to the nuclear test was unequivocal in its condemnation. The foreign ministry in Beijing called it "brazen," strong language for Chinese diplomats to use publicly about North Korea. China still encourages a diplomatic solution with a return to the Six Party talks to resolve the North Korean nuclear issue that North Korea has boycotted since late last year.

China will not act hastily against North Korea. It still remains to be seen what sort of Security Council action she will support. But we can expect Chinese pressure on North Korea to pay more heed to Beijing now that China's interests are being adversely affected by North Korean actions.