The Battle of Bi or Pi was fought in 595 BC, between the armies of Ch'u and Tsin. The battle began when Tsin chariots came out to rescue two of their skirmish units and the Ch'u charged them. The Ch'u began to advance on the Tsin flanks, pushing back the Tsin when 40 Ch'u chariots were committed into the battle. The Tsin began to make a general withdraw. The battle ended with a Ch'u victory. Chu could refer to: The Chu river valley in modern Kyrgyzstan. ...

Reference - Osprey Men-At-Arm/ Ancient Chinese Armies