Zenkei Shibayama (柴山 全慶), a former Abbot of Nanzen-ji, was a Japanese Rinzai master well known for his commentary on the Mumonkan. One of his better-known students was Keido Fukushima, abbot of Tōfuku-ji. Shibayama also taught at Otani University and was the head abbot of the entire Nanzenji Organization, overseeing the administration of over five hundred temples. Due to a number of lecture tours he undertook to the United States in the 1960s, and the translation of several of his books into English, Shibayama was a significant contributor to the establishment of Zen in America.