《黄帝内经·素问·刺法论》
火欲降为在泉之左间，遇水气过胜而地玄阻抑之，则火欲降而不得入，火被抑则发为郁气，待郁气散则火气可入，应当折减其胜气，可以散其郁气。
火欲降而地玄窒抑之，降而不入，抑之郁发，散而可矣，当折其所胜，可散其郁。
Fire intends to descend and stay on the left of the spring. If it encounters the excessive Sheng Qi of Water and the obstruction of the Black Earth, Fire will not be able to descend. When Fire is obstructed, it will transform into U Qi. When the U Qi disperses, Fire can enter. The Sheng Qi should be reduced, and the U Qi should be dispersed.