Eastern philosophy
The "Dao De Jing" ("Tao-Te-Ching," c. 4th century BCE), traditionally attributed to Laozi, and the "Nan Hua Jing" ("Zhuang Zi") are considered the key texts of the tradition. The first organized form of Taoism, the Tianshi (Celestial Masters') school arose in the 2nd century CE. Xuanxue ("deep learning", also "Neo-Taoism") was a major philosophical movement influenced by Confucian scholarship, which focused on the interpretation of the "Yijing," "Daodejing," and "Zhuangzi" and which flourished during the third to sixth centuries CE. The most important philosophers of this movement were He Yan, Wang Bi, the Seven Sages of the Bamboo Grove, Ge Hong and Guo Xiang. Thinkers like He Yan and Wang Bi focused on the deep nature of Tao, which they saw as being best exemplified by the term "Wu" (nothingness, non-being, negativity).
Cheng Yi (philosopher)
Cheng Yi (, 1033–1107), courtesy name Zhengshu (正叔), also known as Yichuan Xiansheng (伊川先生), was a Chinese philosopher of the Song Dynasty. 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.