"Until now the in-fighting appeared to have been between two factions representing Kim's two sons, Kim Jong Nam and Kim Jong Chol, but there are now of another son coming forward," said Toshimitsu Shigemura, a professor of international relations at Tokyo's Waseda University and an expert on North Korean affairs.
"The reports say he is in his 30s and has not been mentioned previously as he has an important role within the military," he said.
The third son, Kim Jong Chol, 28, is believed to have his father's blessing to succeed him, although North Korea's unofficial spokesman in Japan denies that a power struggle is going on and that when the time comes, the most appropriate person for the position will be chosen.
Other key players include Chang Song Taek, a high-ranking party official.
According to Professor Shigemura's sources inside the reclusive country, Kim's health continues to deteriorate and he has only months to live. That has triggered a power struggle that has embroiled the Workers' Party, the military and his powerful family.
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