Inter-promotion means that one thing bears the effect of promoting or generating another in the five elements. The order of inter-promotion among the five elements follows certain rules and forms a circle, i.e. wood promoting fire, fire promoting earth, earth promoting metal, metal promoting water and water promoting wood. The one that generates is called "mother" while the one that is generated is termed "child". So the inter-promotion relationship among the five elements is also called mother-child relationship. Take fire for example. The one that generates fire is wood and the one that is generated by fire is earth. So wood is the mother of fire and earth is the child of fire.

Inter-restraint means that one thing controls and re-strains another thing in the five elements. The order of inter-restraint also follows certain rules and forms a circle, i.e. wood restraining earth, earth restraining water, water restraining fire, fire restraining metal and metal restraining wood. Since the thing being restrained "can not dominate the one that controls it" and the thing restraining another "dominates the one that it controls", the inter-restraint relationship among the five elements is also known as the relationship of domination and submission. Take water for example. The one that restrains water is earth and the one that is restrained by water is fire. For this reason, earth is called the dominator of water and fire is called the submitter of water.

Inter-promotion and inter-restraint among the five elements are in fact inseparable. Without promotion, nothing can grow and develop; without restraint, there will be no way to prevent harm caused by excessive development of things. Only when restraint exists in promotion and promotion in restraint can the normal development and harmonious balance of things be maintained.

     

Besides, inter-promotion and inter-restraint among the five elements restrict each other to avoid harm resulting from excessive promotion and over restraint. For example, wood restrains earth, earth generates metal and metal, in turn, restrains wood. If wood is too powerful, it will over restrain earth and bring on harm. However, metal generated by earth can protect earth by restricting wood. Again take wood for example. 

Only under the normal restraint of metal can wood generate fire. If wood excessively generates fire, fire will become superabundant and turn to restrain metal. Consequently metal will be weakened in restraining wood and wood will become feeble in generating fire. In such a way automatic regulation within the five elements is realized through mutual restriction between inter-promotion and inter-restraint.