Did Korean media publish picture of heir to Asia's last Communist dynasty?

Is it really him? Or is it not him? In the dynastic battle being waged in the hyper-secretive echelons of power in North Korea, the question is of paramount importance.

Did the media in the Stalinist enclave publish a photograph of Kim Jong-un, the youngest son and believed successor of the Dear Leader, Kim Jong-il? This would make it his first appearance in the media and, therefore, a critical moment in North Korea's mysterious history.

The photograph first published in the North Korean newspaper Rodong Sinmun on 5 March purported to show the 26-year-old standing beside his father on a steel factory inspection in Hamgyong Puk Do, in the country's north-east. A Japanese newspaper insists that it is Kim Jong-un. If so, he is a foot taller than his father, and their sartorial styles are different. Jong-un has no quiff and is not wearing a grey jumpsuit.

Since he is the likely successor to Kim Jong-il, the photograph's publication will be minutely analysed by those devoted to predicting the future of Asia's final Communist dynasty. The questions have become more urgent since Kim Jong-il, who is 67, suffered a stroke in August 2008.

Although North Korea's economy is said to be reeling from the impact of United Nations sanctions, a third nuclear test was reported yesterday to be on the way.

Pyongyang has never issued a statement saying Kim Jong-un will be the successor but the regime does not issue many press releases. Korea-watchers have to read between the lines for clues as to what is going on in the country.

Kim Jong-un is the Swiss-educated third son of Kim Jong-il and was born in 1983 or 1984 to his late wife, a Japanese-born professional dancer called Ko Yong-hui. Kim Jong-il has been trying to introduce him as his successor for months, and has asked the country's main bodies and overseas missions to pledge loyalty to him.

The Japanese newspaper Mainichi Shimbun reported that it had sources close to the leadership confirming that the photograph was indeed Kim Jong-un. It also cited South Korean intelligence sources.

Other South Korean officials say the photograph is not real. "The photo is not of Kim Jong-un," a Unification Ministry official said in Seoul in comments run on the Yonhap News Agency. The South Koreans say it shows an executive of the Kim Chaek Iron and Steel Complex.

Previous pictures of Kim Jong-un show that he has his father's sceptical and appraising glance, one not without humour but at once disdainful. That's if it is, indeed, Kim Jong-un.

He is said to be fond of a drink and to be a good English and German speaker. He may be a diabetic. He is supposedly a tough decision-maker. Like so much of the information about this strange family, the information is at best sketchy and may be tainted by misinformation by South Korean intelligence services.

Some reports have said that Kim Jong-un's appointment is a done deal, evidenced by his appointment to a senior position in the ruling Korean Workers' Party. Some analysts believe that North Korea's nuclear weapons programme, and the manner in which Pyongyang has taken on the world, is a complicated act of defiance to convince the powerful North Korean army that the dynasty is strong enough to continue via the Dear Leader's youngest son. Claimed sightings have been wrong before. In June last year a Japanese TV station showed a photograph of what was said to be Jong-un, but which turned out to be that of a South Korean construction worker.