The only thing known for certain is that Kim Jong Il's special armored train was seen on the move in the direction of China.
A buzz of speculation immediately began in South Korea on what could be the purpose of a new visit to China by Kim, which would follow one he made to Beijing in May.
The general consensus seems to be that the ailing 68-year-old leader has gone to introduce his youngest son and presumed successor, Kim Jong Un, to the Chinese leadership.
Next month sees the first meeting for years of the top organs of the North Korean Workers' Party, which Reuters noted would select new party leaders and may give Kim Jong Un an official party role and formally initiate the grooming for succession.
Introducing the young man to Chinese leaders at this time would therefore seem appropriate. China is North Korea's only main ally in the world, and Beijing would want to know that the same close ties would persist under the son as under the father.
China, despite its liberalized economy, views communist North Korea as a key ideological buffer between it and the influence of the West, which begins with South Korea.
Kim Jong Il's ability to lead North Korea has been in question since he reportedly suffered a stroke in 2008. Making clear the line of succession would also have advantages for him on the domestic scene, by removing the air of uncertainty that has built up since his health began to fail.Mysterious As His Father
Very little is known about Kim Jong Un, not even his birth date. The youngest of Kim's three known sons, he is Swiss-educated and thought to be in his mid-20s -- not an advantage in a society that values age and experience. But he is said to have the same ruthless streak and will to govern as his father.
His views on policy are completely unknown, but as his father's favorite it seems inevitable that he espouses the same deeply isolationist line as his father, and also a centralized economic system that has proved disastrous for his poverty-stricken country.
The presumed visit to China comes at a moment when former U.S. President Jimmy Carter is in Pyongyang on a humanitarian mission
to secure the release of an American peace activist being held prisoner by the North.
It's not clear whether the apparent absence of Kim Jong Il from the capital at this time has affected Carter's mission to rescue Aijalon Mahli Gomes.compiled from agency reports