If the enemy has occupied them before you, do not follow him, but
retreat and try to entice him away.
The turning-point of 李世民 Li Shih-min’s campaign in 621 A.D.
against the two rebels, 竇建德 Tou Chien-tê, King of 夏 Hsia, and
王世充 Wang Shih-ch‘ung, Prince of 鄭 Chêng, was his seizure of the
heights of 武牢 Wu-lao, in spite of which Tou Chien-tê persisted in
his attempt to relieve his ally in Lo-yang, was defeated and taken
prisoner. [See _Chiu T‘ang Shu_, ch. 2, fol. 5 _v_^o and also ch.
54.]