The Mumonkan, translated as The Gateless Gate, is a collection of 48 Zen koans compiled in the early 13th century by the Chinese Zen master Mumon Ekai (1183-1260). Along with the Blue Cliff Record, The Gateless Gate is a central work of the Rinzai School of Zen Buddhism. The common theme of the koans of Mumon Ekai, nature of dualistic conceptualization. Each koan epitomizes one or more of the polarities of consciousness that act like an obstacle or wall to the insight. The student is challenged to transcend the polarity that the koan represents and demonstrate or show that transcendence to the Zen teacher.