The term means reducing the exuberance of one element through the successive restriction effects among the five elements to restore the balance. Alternate preponderance among the five elements is a form of self-regulation in accordance with the principle of restriction. There are two situations that preponderance qi occurs: 1) one element being excessive, which manifests itself as absolute exuberance; and 2) a weak element causing the element that restricts it becoming comparatively exuberant. Retaliation qi is generated by the occurrence of preponderance qi, i.e., preponderance qi occurs before retaliation qi. Retaliation qi comes to “revenge” preponderance qi, bringing it to balance. Through this regulation mechanism, the five-element system can perform its self-regulation function to maintain its overall balance when part of the system is in disharmony.