By Jill McGivering
It is not clear if Kim Jong-il shares powers with his top generals
There is mounting speculation about the health of North Korean leader Kim Jong-il after he missed the country's 60th anniversary parade.
But why is his failure to attend the focus of so much attention?
With so little information about what happens in North Korea, every scrap becomes significant.
For Kim Jong-il not to preside over anniversary celebrations is extremely unusual.
He has become the focus of rumours about his health partly because he is such an enigmatic and reclusive figure.
He rarely travels, apart from occasional visits to Beijing by train. He rarely appears in public and then at stage-managed events.
He is surrounded by an inner circle of relatives and trusted advisers.
It is rare even for diplomats based in Pyongyang to meet him personally.
He is also the subject of a rigorous personality cult. North Korean children learn special songs to praise him. The official version of his life gives him a heroic, almost divine status.
N Korea marks 60th anniversary
In contrast, South Korea paints him as a figure of fun - a foolish playboy with extravagant tastes.
The truth may be less extreme.
He matters so much because he is the country's main political focus. But it is less clear whether power really is vested in him as an individual - or shared by top generals.
Without him, though, North Korea might enter a period of uncertainty.
There is much speculation about who might succeed him - but possible rivalries between his half-brother and three sons are hard to confirm.
It would be fascinating to know how much of all this North Koreans themselves have heard.
Information is tightly controlled. Access to anything other than state radio and television is strictly punished.
The issue of Kim Jong-il's health is so sensitive, it is said to be an offence even to talk about it in public.