Kim Jong Il reminds me of Mao Zedong. The Chinese dictator, when he was alive, lived behind an impenetrable wall of secrecy, so that very few knew anything about his life and his world, including where he lived or where he was. When Mao flew, every other plane in China was grounded. When his special train moved, the country’s railway system was thrown into chaos as other trains were not allowed to be anywhere near his.

“Throughout his reign, he lived in his own country as if in a war zone,” wrote Jung Chang and her husband Jon Halliday of the Chinese communist monster in their “Mao: The Unknown Story.” Wherever Mao might set foot, the grounds were swept by Russian mine detectors and Chinese soldiers walking shoulder-to-shoulder as human minesweepers.

One episode described in “Mao” was particularly telling. On the eve of his inauguration as China’s supreme leader, deep fear was lurking in the recesses of Mao’s mind. Madame Mao told a visiting friend that the chairman was all right, “except he would tremble when he saw strangers.” The visitor was puzzled as Mao looked well. Mao then interjected: “You are an old friend, not a stranger.” Ms. Chang and Mr. Halliday said, “It seems Mao knew that his terrorization had produced not only mass conformity, but quite a few would-be assassins.”

The “Dear Leader” from North Korea also seems to be suffering from the same paranoia. Mr. Kim’s recent visit to China, his fourth since 2000, was so secretive that it was not confirmed by Beijing and Pyongyang until after his train had left China.

Like father, like son. Mr. Kim, like his father Kim Il Sung, the founding father of the Democratic People’s Republic of Korea, is thought to have an aversion to flying and has almost always traveled by train under tight secrecy on his rare visits abroad. The stealth underscores Mr. Kim’s insecurity. Shortly after his last trip to China in April 2004, an explosion took place on a railway line used by him.

Mr. Kim, paying an “unofficial” visit to China from January 10 to 18, went to six cities and met with the entire top Chinese leadership, according to China Daily. Mr. Kim toured the southern city of Shenzhen, right north of Hong Kong, where, as a special economic zone, capitalism was first allowed after the death of Mao. Mr. Kim was said to be greatly impressed by the result of China’s reform and opening-up policy. It gives hope to some that North Korea might follow its big brother’s footsteps. The Chinese message to the North Korean guest, I think, is more likely to be: “Don’t worry about opening up the economy. Look, we still can keep a tight lid on politics.”

Another southern city that Mr. Kim paid a visit to was Zhuhai, adjacent to the former Portuguese colony of Macau. Last September, the U.S. Treasury Department ordered all American financial institutions not to do business with Banco Delta Bank in Macau. The bank was accused of spreading counterfeit money printed in North Korea and laundering money earned through drugs and weapons of mass destruction. The fake $100 bills, called “supernotes,” are considered the highest-quality forgeries in the world. Macau authorities later seized the bank and supposedly put a stop to its dealings with Pyongyang.

In this, perhaps, lies the real reason for the visit. Hurt by American sanctions, Pyongyang must turn to its only close ally for help. Mr. Kim was quoted by the Chinese state press thanking Chinese leaders “for rendering disinterested assistance” to North Korea “each time it faced difficulties.”

China has become the main source of fuel and consumer goods for North Korea, estimated to supply at least 40% of its food and 90% of its oil. After the visit of the Chinese Communist Party chief, Hu Jintao, to Pyongyang last October, North Korea was reportedly to have received as much as $2 billion in aid.

Interestingly, just when Mr. Kim was leaving China, the assistant secretary of state, Christopher Hill, the top American negotiator in the six-party talks, made a brief and apparently unscheduled return trip to Beijing at the end of a visit to the region. Song Min-soon, the South Korean negotiator, was also reported to have made an unannounced visit to Beijing around the same time. Mr. Hill, trying to revive the stalled talks, declined to confirm or deny that he had met any North Korean official.

The six-party talks, involving America, China, Russia, Japan, and the two Koreas, perhaps not unexpectedly, do not seem to be moving toward the goal of disarming Pyongyang. “In an epoch it is supposed to dominate, America has been reduced to relying on China – the other side’s best friend – to craft a solution critical to its future. What kind of policy is that?” asked Gordon Chang, author of the newly-released “Nuclear Showdown: North Korea Takes On the World.”

Skeptical of Beijing’s effort in pushing its North Korean friends to give up the nukes, last year I had a chance to ask Mr. Hill what he thought China could do more to help. He said, “We need to solve it and the Chinese understand that better than anybody.” The hope is that Beijing will decide to become a stakeholder and impose the right solution on Pyongyang. But don’t bet on it.

China, if it wishes to, could almost unplug and switch off North Korea overnight. Considering a controlled crisis in the Korean Peninsula is an issue for the Yankees only, Beijing is going through the motions to help Washington, hoping to get something in return: Taiwan. Mr. Chang said that the Chinese have repeatedly suggested that for China to give up North Korea, America has to agree to abandon Taiwan. “That deal, which envisions the destruction of an emerging democracy, is too cynical to contemplate,” he wrote.

Being resolute remains America’s best tool in dealing with North Korea. I agree with Mr. Chang’s suggestion: “If China believed that America was about to resort to force, it would do most anything to prevent regional conflict, perhaps even apply real pressure on Pyongyang.” In February 2003,China cut off oil for three days. In June 1994, China voiced the possibility of stopping food and oil supplies. Both times, North Korea took the hint and softened its position afterward.

Mr. Liu is a former Washington-based columnist of Hong Kong’s Apple Daily.