Capítulo 143: Thunder Research Center.

For the next month, there was not much turbulence and life passed peacefully. Hao Ren and Han Lingshi were diligent with their cultivation and they were progressing forward quickly. To hold the spiritual energy within their bodies, the two of them needed to open their Dantian. 

It was a difficult and painful process and they were told to do it slowly. Even in their cultivation sutras it was mentioned that a cultivator should not attempt to force open the Dantian as it could lead to drastic consequences and even ending up being unable to cultivate was a possibility. 

The method that Hao Ren used was to control the spiritual energy and have it grind away at the opening gate of the Dantian which laid above the stomach. Dantian was the empty space between the organs which created a pressure inside the body to complete the breathing mechanism.