All About Kim Jong Un

Ken Gause may be the best open-source expert on North Korean kremlinology who writes in the English language, and he has an extensive survey of what we know about Kim Jong Un at Foreign Policy:

In February 2009, Yonhap reported that Jang (director of the KWP’s Administrative Department, which oversees much of North Korea’s security apparatus) had shifted his support to Kim Jong-un in light of Kim Jong Il’s “special affection” for his third son and out of consideration for his own future political power. According to senior North Korean defectors in South Korea, Jang reached a deal with Kim Jong Il. Worried about being purged, as he was in 2004 for becoming too powerful within the regime, Jang agreed to throw his support behind Kim Jong-un. In return, Kim Jong Il has allowed Jang to engineer the succession by placing his allies in key posts throughout the regime. Many of the recent key appointments allegedly have Jang’s backing. The new chief of the general staff, Yi Yong-ho, is allegedly close to Jang, as is the new minister of the People’s Armed Forces.  [Ken Gause, Foreign Policy]

Myself, I consider this detail to be interesting but not terribly significant.  I doubt that Jong Un has the gravitas, connections, or cred to rule that nest of vipers.  Jang, on the other hand, just might.