As North Korea-watching reaches new heights in the build-up to Kim Jong-il's funeral next week, many in the region are wondering about the whereabouts of his eldest son, Kim Jong-nam.
Jong-nam, who lives in Macau, has not appeared in public this week and his name is absent from the 232-strong committee organising his father's state funeral in Pyongyang.
Diplomats who follow his movements say he travels frequently in the region but has not visited the North Korean capital since his youngest half-brother Jong-un - now hailed as the 'great successor' - emerged as heir-apparent following his father's stroke in mid-2008,
Jong-nam, his father's natural successor under the Confucian precepts that underpin communism's only dynasty, was groomed for the top job and given a series of sensitive technology and security positions within the feared security apparatus. But all that changed when he was detained by Tokyo immigration police in 2001.
He was attempting to enter Japan on a false Dominican passport bearing a Chinese name, and told officials he wanted to take his children to Disneyland. He was detained for several days and deported to China.
Since then, he has spent long periods in Macau and Beijing, living in hotels and secure apartments, while frequently visiting France, Austria and Bangkok - and, until 2009, Pyongyang too.
His whereabouts now is not a matter for idle speculation. Senior government officials in Seoul and Tokyo believe he may yet be pressed into service should Jong-un, who is only in his late twenties, struggle to handle a transition that must see him deal with various military and Workers' Party factions.
'He may well be a second back-pocket option, and one very useful to Beijing,' said one veteran Asian diplomat who has met Jong-nam on several occasions.
'He's not the fool the Disneyland episode has painted him to be,' the envoy said. 'We know he is highly intelligent and internationally minded, even a potential reformer. His life-style, of course, is another matter - but that's par for the course in the Kim dynasty.'
When the South China Morning Post revealed his Macau bolt-hole in early 2007, it was clear he was not there for the churches.
Jong-nam, based in various hotel suites and a luxury apartment on Coloane, spent long nights drinking heavily, eating and visiting nightclubs, a fact reflected in his bowling-ball physique.
While North Korean minders working out of Shenzhen provided him protection, he was able to mix with a variety of friends of different nationalities, including Australians and Russians.
His Macau years have frequently been painted as exile, and yet they coincided with a period during which the enclave was a vital link in Pyongyang's shadowy foreign banking and trading activities. North Korea has no means to move money electronically, and strongboxes of gold and cash hand-carried to Macau were one of its few banking outlets.
This led to diplomatic speculation that Jong-nam was performing an important role overseeing the finances of the ruling elite.
Jong-nam's second wife and mistress have been based in Macau in recent years, while his first wife is thought to live in Beijing. His son Kim Han-sol was educated at an international school in Macau.
The Post revealed in October that Han-sol had been denied a visa by the Hong Kong government, a move that scuppered plans by the local Li Po Chun United World College for him to study there. He has now enrolled at a sister school in Bosnia-Herzegovina.
While the speculation mounts ahead of his father's funeral, one thing is clear: publicly at least, Jong-nam has shown little interest in the succession. In a rare interview with Japan's TV Asahi as he passed through Beijing airport in October last year, he said he opposed 'hereditary succession for three generations. But I presume there were internal reasons. We should abide by such reasons if there are any. I presume my dear father decided ....' He added: 'I have no objection or interest in the succession. I do not care about it at all.'