C340 Unfathomable
After Chen Hui's punch landed on Zhang Jie, he retreated two steps and did not continue attacking Zhang Jie, because he knew very well how strong he was, and knew that this punch of his was enough to make Zhang Jie lose his fighting strength.
The sides of a human's ribs, belongs to the weak parts of the human body. Chen Hui didn't actually use much strength with this punch