The entire I Ching is concerned with the relationship between yin and yang… When yin competes against yang, it reveals the yin aspect; then yin represents evil instead of yielding.
Huang argues that the I Ching’s governing concern is the yin-yang relationship, insisting that yin’s proper mode is yielding complementarity, while competitive yin becomes a destructive, evil force.
, The Complete I Ching: The Definitive Translation, 1998thesis