Mumon Yamada (山田 無文, Yamada Mumon; July 16, 1900 – December 24, 1988) was a Rinzai roshi, calligrapher, and former abbot of Shōfuku-ji in Kobe, Japan. Mumon was also the former head of the Myōshin-ji branch of the Rinzai school of Japan. His most prominent student (and Dharma heir) is Shodo Harada of Sōgen-ji, an influential master in both Japan and the United States.
Source: “Mumon Yamada”, English Wikipedia (CC BY-SA 4.0), excerpt