Literature Reference: 取其向背性，制在饥饱时。—— 《放鹰》 Take its nature of facing or turning away, control it in times of hunger and fullness. Source from 'Fang Ying'.
向: Facing, confronting. In contrast to "turning one's back."
背: The part of the torso opposite to the chest and abdomen.
Meaning: Facing or turning away implies the duality of things, symbolizing flexibility and adaptability.