Cheng Yi (1033–1107), also known by various other names and romanizations, was a Chinese classicist, essayist, philosopher, and politician of the Song Dynasty.[1] He worked with his older brother Cheng Hao. Like his brother, he was a student of Zhou Dunyi, a friend of Shao Yong, and a nephew of Zhang Zai. The five of them along with Sima Guang are called the Six Great Masters by his follower Zhu Xi. He became a prominent figure in neo-Confucianism, and the philosophy of Cheng Yi, Cheng Hao and Zhu Xi is referred to as the Cheng–Zhu school or the Rationalistic School.[2]