Born into a family from Kaifeng in Henan Province, Zhang Zai, styled Zihou, lived in a small town called Hengqu of Mei County in modern Shaanxi Province for the major part of his life and hence was known as Hengqu. After a few years of strenuous study of Daoism and Buddhism, he was encouraged by Fan Zhongyan to study Zhongyong (The doctrine of the mean) when he was only 21. He thus left Daoism and Buddhism behind and returned to the Confucian classics in a quest for a philosophy of the Confucian Way (dao). Like Zhou Dunyi, Zhang Zai finally set his mind on the Yijing (Book of changes) and change (yi) as the very essence of the Way. Zhang Zai's main work was Zheng meng (Rectifying the obscure), in which he developed his metaphysics of vital energy (qi). In this treatise he became the...