(1183 - 1260)
Wumen Hukai was a Chan master born in the Hangzhou prefecture of China. He is best known for writing The Gateless Gate, a collection of forty-eight Zen koans. In its famous first koan, known as the “mu koan,” Chan master Zhaozhou Congshen is asked whether a dog has the Buddha nature. As a young monk, Wumen is said to have spent six years struggling with the koan.