Who is Wu men huikai?

Wu Men Huikai, also known as Wumen Huikai, was a Chinese Zen Buddhist master and a prominent figure in the 12th century. He is best known for his work "Wumen Guanzhu," or "The Gateless Barrier," a collection of koans that has become essential in Zen practice. His teachings emphasized direct experience and the importance of realizing one's true nature. Wumen's influence remains significant in Zen Buddhism, shaping the way koans are used in meditation and teaching.