Zhang Liang 張良 was the noble descendant of State of Han during the Warring States Period. His father, grandfather and great-grandfather were all officials of the State of Han. Zhang Liang had once planned an assassination against Qin Shi Huangdi but the employed assassin mistakenly destroyed the decoy vehicle. Zhang was then forced to flee. The attempt was the origin of a famous Chinese four-character idiom, 誤中副車. He later joined Liu Bang to rebel the rule of Qin and helped him to establish Han Dynasty. He soon retired and became a practitioner of Taoism.
Legends recounted that Zhang Liang had once helped an old man to put on his shoes and was rewarded a book on military strategy and tactics.