So little is known about Kim Jong-un - the youngest son and reportedly the named successor of North Korean leader Kim Jong-il - that even his date of birth is uncertain: no-one is really sure whether he was born in 1983 or 1984.
But it is known that the third Kim, like his two elder brothers, was sent to school in Switzerland. The BBC's Imogen Foulkes reports on the young Kim's school days, and the unusually close relationship between Switzerland and North Korea.
Reports claim Kim Jon-un has been chosen as the North's next leader
Kim Jong-un attended Berne's international school, where, it is rumoured, he joined school skiing outings, and was something of a peacemaker in playground disputes.
He arrived every day in a chauffeur-driven car from the North Korean embassy, which is just around the corner from the school.
But, since Jong-un went under an assumed name, none of his classmates knew his true identity.
He is said to have been closely supervised by embassy officials - but he also apparently speaks Swiss German - and since the language of the international school is English, that indicates that the young Kim did spend some time socialising.
The choice of a Swiss education for North Korea's future leader may not be a coincidence.
North Korea's ambassador to Switzerland has been in his post for more than 20 years and North Korea watchers regard Ri Tcheul as extremely powerful, enjoying the confidence of Kim Jong-il.
Switzerland has surprisingly close ties with North Korea.
During the famine of the 1990's the Swiss launched a substantial humanitarian relief operation, which, almost alone among foreign aid projects, was subsequently transformed into a long-term development programme.
In 2003 Switzerland's foreign minister was the first foreign government official to cross the demarcation line between North and South Korea.
At the time she offered Switzerland's services as a mediator between the two Koreas.
And every year North Korean officials come to Switzerland, ostensibly to study the Swiss federal system - the most recent visit was in February.
North Korean agricultural specialists regularly spend time here studying the Swiss art of making cheese and yoghurt, which Kim Jong-il is said to love.
But recently, there are signs that warm relationship may be cooling.
The two biggest Swiss banks, UBS and Credit Suisse, stung by allegations that Kim Jong-il was storing billions in Switzerland, announced in 2006 that they were cutting ties with North Korea.
Meanwhile, Switzerland's development programme is set to end in 2011, amid rumours Swiss financial aid was going not to North Korean farms, but into the coffers of the government in Pyongyang.
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