Why has North Korea announced his ousting so publicly?
"The regime may well have had no choice, since the masses are no longer cut off from outside news sources and it would be worse to let rumour run amok, perhaps turning Jang into a positive figure," says Brian Myers, an expert on ideology and propaganda at Dongseo University in Busan. "On the other hand, ascribing a counter-revolutionary motive to someone with such close ties to the Kim dynasty itself seems to me a bad move. First, it explodes the cherished myth of complete North Korean unity. Second, it implies criticism of the late Kim Jong-il. If the Dear Leader could not see what a bad person Jang was, how are the masses to trust in the wisdom of his choice of successor?"
Who made the decision to remove Jang?
Andrei Lankov, of Kookmin University in Seoul, and others, believe Kim Jong-un is consolidating his power.
But others are not so sure. "In my view, we cannot even say really if Kim Jong-un was behind this or what exactly this means about Kim. It is done in his name, but it is done by the elite as a group," says John Delury, of Yonsei University, Seoul. "This tells us there have been major power struggles during what looked like a very smooth transition. We can see from North Korea's own acknowledgement it has been anything but smooth."
Where does this leave politics in North Korea?
"The situation is delicate, fragile and uncertain," says Cheng Xiaohe, of Renmin University in Beijing.
Lankov expects to see a new generation moving into power, but from very similar backgrounds, producing "a new leadership composed overwhelmingly of the grandchildren of people currently in control". He anticipates a large cull of top civilian workers; Jang sought to restore the role of civilians within the elite. That does not mean, however, that military elements have triumphed. "We have a game of musical chairs around the top military command. People are being replaced with unbelievable frequency," he says.
Could this affect the apparent economic changes happening in North Korea?
Many analysts associate Jang with changes including opening up special economic zones for foreign investors, leading some to surmise that his removal will end such changes. "The ones they have already set up with China are lying fallow and Jang is associated with those. That's disconcerting," says Adam Cathcart, a Chinese history lecturer at the University of Leeds, in northern England.
Lankov argues that purging Jang could usher in more sweeping changes. "My guess is that [Kim] is going to start reforms," he says. "Economic reforms in North Korea are difficult and dangerous and you have to be brutal to keep stability."
How will this affect North Korea's relations with the outside world?
Yonsei University's Delury says the move underscores the need for countries to work with North Korea and hold regular meetings. "The more we talk with their leaders the better sense we have of what's going on," he says.