Battle of Changping
In 259 BC, the Qin army massacred 400,000 Zhao soldiers at the Battle of Changping, and besieged Handan, the capital of Zhao, the following year. Zhao sought help from Chu; Lord Chunshen led the Chu army to Handan, and successfully relieved the siege. In 256 BC, Lord Chunshen attacked the State of Lu, and annexed the state for Chu.