Ta-chu Hui-hai

A T'ang dynasty Chinese Ch'an monk. Very little is known of him, including the dates of his life, other than that he was a disciple of the famous monk Ma-tsu Tao-i (709-88), and that he wrote the influential treatise Essential Gate for Entry Into Sudden Enlightenment (Chinese, Tun-wu ju dao yao-men), which is still extant.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)