Such a visit just days before the 100th anniversary of Japan's colonization of Korea carries symbolic weight as well. North Korea tends to play up the Kim family's patriotism during succession campaigns.
Kim Jong Il watchers will be eager to see television footage or photos of the 68-year-old leader to check his health. In video run by Chinese Central Television in May, Kim appeared thin but vigorous during meetings with China's President Hu Jintao and other officials, despite having reportedly suffered a stroke in 2008.
South Korea's Yonhap News Agency reported that Kim checked into the Jilin Crystal Hotel, and roads leading to the secluded luxury hotel were blocked by police.
The hotel's website advertises plush suites, a billiard room, swimming pool and sauna, with a scrolling banner in broken English that reads: "Loosely expressing one-self and let the mood flying high."
It wasn't clear how many rooms Kim booked but Yonhap and YTN television in Seoul said he may be traveling with a son to consult with Chinese officials on succession plans.
It's widely believed that Kim is preparing to transfer power to his third and youngest son, Kim Jong Un, and many North Korea watchers predict the son will be appointed to a key party position at a rare ruling Workers' Party meeting early next month.
"Kim is at a crucial crossroads — whether to hold the party's conference as scheduled or delay it until after they've recovered from floods," said Cheong Seong-chang, a senior analyst at the Sejong Institute think tank outside Seoul. "Kim desperately needs Chinese food aid to hold the party's conference as planned."
The flooding earlier this month damaged or destroyed more than 7,000 homes, and wiped out bridges and railways, the North's official Korean Central News Agency reported Thursday. China has already offered aid to help North Korea cope, KCNA said.