Kim Jong Il's China trip unfolded amid the usual bizarre secrecy that highlights both the North Korean dictator's cloistered ways and the singular relationship between his hard-line communist regime and its most important ally.
While Kim has grown ever more dependent on Chinese aid and diplomatic support, Beijing appears determined to do what it takes to prevent his regime's implosion and the potential political chaos that could bring severe unrest to its border regions.
That mutual interdependence goes far in explaining China's willingness to acquiesce in the farcical spectacle of obfuscation and denial that defined Kim's four-day trip that was believed to have wrapped up on Thursday.
"China accepts North Korea's request for secrecy, considering their special relations," said Kim Yong-hyun, a North Korea expert at South Korea's Dongguk University.
On Thursday, Chinese Foreign Ministry spokeswoman Jiang Yu pleasantly maintained her insistence on claiming ignorance about the visit - but indicated word would be forthcoming.
"In keeping with past practice, if top (North Korean) leaders come for a visit, relevant information will be released at the appropriate time," Jiang said to reporters.
A motorcade left the Diaoyutai State Guesthouse, where foreign dignitaries often stay, on Thursday afternoon, arriving shortly afterward at Beijing's South Station from which Kim's train left a short time later - destination unknown.
Kim met with Chinese President Hu Jintao on Wednesday night and with Premier Wen Jiabao and other officials on Thursday, according to reports in South Korean media, which have closely followed the visit.
Kim is thought to have arrived Monday on the special armored train he uses because he shuns air transport. This week's visit is his fifth to China since succeeding his father as ruler in 1994, with the last in 2006.
Ailing from what was believed to have been a stroke in 2008, Kim, 68, is rarely seen in public and is surrounded by tight security at all times. His movements are never announced until his trips are finished, but several journalists have spotted him in Beijing and rare footage of Kim has been captured by several TV broadcasters.
South Korea's Yonhap news agency reported that Kim told Hu he is ready to return to six-nation denuclearization talks, but it gave no details. Kim has said the same thing in the past, but usually with attached conditions, such as a long-sought direct dialogue with the United States. Yonhap did not say what, if any, conditions he set this time.
Scholars have said they expected Kim to express some new willingness to rejoin the long-stalled China-sponsored negotiations, under which North Korea agreed to dismantle its nuclear programs in return for aid.
North Korea quit the talks a year ago and then conducted a nuclear test that drew tightened U.N. sanctions. The last round of the talks - involving China, Russia, the two Koreas, Japan and the U.S. - was held in December 2008.
Although China is unlikely to link them explicitly, a return to the talks is likely to go hand-in-hand with new aid, including the implementation of economic agreements reached during a visit by Wen to North Korea last year.
China, which sent troops to back North Korea during the 1950-53 Korean War, already provides the bulk of its food and fuel aid to feed its malnourished population of 23 million and prop up an economy devastated by natural disasters and chaotic management - most recently a currency revaluation that backfired disastrously.
Beijing's support for Kim is driven overwhelmingly by its own security concerns, which override any unhappiness it might have over North Korea's nuclear program or rejection of economic reforms, Chinese scholars say.
"No matter how different its opinions are from those of the North Koreans, and how much unhappiness it has toward them, the Chinese government will not leave North Korea to implode, and it will not let the strategic balance of the Korean peninsula be broken," said Cai Jian, deputy director of the Center for Korean Studies in Shanghai's Fudan University.
That, however, comes at the risk of upsetting South Korea, where suspicion is rising that a North Korean torpedo destroyed the naval ship Cheonan in March, killing 46 sailors. North Korea has denied involvement.
Trip's Timing Leaves S. Korea Piqued
The timing of Kim's China visit has aroused some complaints among South Korean politicians, who say it shows insensitivity toward the Cheonan victims. South Korean officials have asked that China play a "responsible role" in the aftermath of the sinking and keep them informed of Kim's activities in China.
The sinking is expected to come up in three-way security talks among the foreign ministers of South Korea, Japan and China next Saturday, according to Yonhap.
"I believe not only our country, but also the United States, China and all the other related nations share a mutual understanding on the seriousness of the Cheonan incident," it quoted Foreign Ministry spokesman Kim Young-sun as saying.