Hai (Harm) is a covert damaging interaction between Earthly Branches, also known as 'Chuan' (Piercing). The Six Harm relationships are: Zi harms Wei, Chou harms Wu, Yin harms Si, Mao harms Chen, Shen harms Hai, and You harms Xu. Hai primarily signifies covert harm, suspicion, and disharmony; encountering Hai leads to strained interpersonal relationships, though its influence is weaker than that of Clash (Chong) or Punishment (Xing).
Examine whether any of the Six Harm relationships exist among the Earthly Branches in the four pillars of the八字 (BaZi). The Six Harm pairs are: Zi harms Wei, Chou harms Wu, Yin harms Si, Mao harms Chen, Shen harms Hai, and You harms Xu. When any two branches form one of these six pairs, Hai is present. Hai often arises from Combination (He) or Clash (Chong); Combination gives rise to Harm.
In a BaZi chart, if the Year Branch is Zi and the Day Branch is Wei, Zi harms Wei — indicating covert disharmony in relationships with elders or one’s spouse.