The stunning execution of Kim Jong Un's powerful uncle strips China of its most important link to North Korea's leadership and deepens concerns over how the unruly neighbour will proceed on Beijing's key issues of nuclear disarmament and economic reform.
Facing heightened uncertainty, Beijing will likely avoid, for now, any response that might boost panic or paranoia in Pyongyang, where China is both valued and resented as a key backer of Kim's regime.
"It's like when you have a gas leak. You want to be very, very careful not to set off any sparks," said Jingdong Yuan, an expert on northeast Asian security at the University of Sydney.
At the same time, China is likely dusting off its contingency plans for instability or even a regime collapse that could see thousands of refugees swarming across its borders, put the North's nuclear facilities at risk, and prompt action by the United States and South Korean militaries, Yuan said.
Jang met with top Chinese officials during their visits to Pyongyang, and in 2012, Jang travelled to China at the head of one of the largest North Korean delegations ever to visit the Chinese capital to discuss the construction of special economic zones that Beijing hopes will ensure North Korea's stability.
His execution on a myriad of charges from treason to drug abuse further diminishes China's narrow influence on the government of the younger Kim.
Despite being North Korea's only significant ally and a crucial source of trade and aid, Beijing has been unsuccessful in persuading North Korea to rejoin a six-nation nuclear disarmament talks, while its overwhelming desire for stability along its northeastern border prevents it from getting overly tough on its neighbour.