Di Tiansui
Calling Yin Xingsi means Yin wood generates Si fire. We also know that Yin Wu
Half fire situation means that fire is strong. Then Yin and Si's mutual punishment is the meaning of Yin and Si's half-combined fire situation.
Therefore, the punishment between Yin and Si is also a sign of strong fire.
Just like Yinwu half-combination, there must be a
fire
thoroughly dry
(i.e. Bingyin and Si or Dingsi and Yin). Constituting the punishment of Yin and Si