Final answer:
In the sheng cycle, to tonify a deficiency, one would strengthen the element that precedes the deficient element in the productive sequence of the Five Phases (wuxing) system.
Step-by-step explanation:
In the sheng cycle of the Five Phases (wuxing) system, to tonify means to strengthen or enhance a certain element. If there is a deficiency, one should boost the element that is next in the productive cycle. In wuxing, each element supports another: Wood fuels Fire, Fire creates Earth (ash), Earth bears Metal, Metal collects Water, and Water nourishes Wood. Hence, to address the deficiency, you would tonify the element that precedes it in this cycle to strengthen it.
For example, if there is a deficiency in Water, you would tonify Metal to enhance Water, as Metal brings forth Water. This principle not only applied to environmental and bodily health but also extended to sociopolitical realms, as harmony in one aspect of the cosmos was believed to reflect harmony in all. The historical concept of harmonizing oneself with the prevalent phase to ensure overall health is a reflection of this ancient Chinese cosmological perspective.