Yi Xing

For the Vietnamese monk with the same Chinese dharma name, see Thích Nhất Hạnh. For the city in Jiangsu, see Yixing. For the member of EXO, see Lay (entertainer).
Painting of Yi Xing from the Shingon Hassozō, a series of scrolls depicting the first eight patriarchs of the Shingon school of Buddhism. Japan, Kamakura Period (13th-14th century)

Yi Xing (Chinese: 一行; pinyin: Yī Xíng; Wade–Giles: I-Hsing, 683–727), born Zhang Sui (Chinese: 張遂), was a Chinese astronomer, Buddhist monk, inventor, mathematician, mechanical engineer, and philosopher during the Tang dynasty. His astronomical celestial globe featured a liquid-driven escapement, the first in a long tradition of Chinese astronomical clockworks.