Zengaku 禪學, the scholarly study of Zen, is a prime reason why the Japanese pronunciation 'Zen' is used in European languages as an omnibus term for Chinese Chan, Korean Seon (alt. Sŏn), Vietnamese Thiền, and Japanese Zen. Zengaku, the philological and historical study of Zen was chiefly developed in Japan and came to prominence just as Japan was opening to the West. These Zen proponents promoted Zen to the West as essentially Japanese, largely ignoring Chan, Seon, and Thiền. Within East Asia, the works of Zengaku scholars pioneered the academic or scholarly study of Zen, Chan, and Seon. Zengaku scholars produced the first dictionaries of Zen, the earliest histories, bibliographical studies and text editions. Their works became the basis for Chanxue and Seonhak. This essay examines the scholarship that modernised Zen and brought it to the attention of the modern world under the name Zengaku. It will examine the condition and status of Zen in East Asia from the 1870s to 1920s and then the knowledge available to non-East Asian audiences in the same period. Following this, it will describe the promotion of Zen to the West and a modern Japanese audience by Zengaku scholars. Lastly, it will examine the precursors of Zengaku, especially the work of Mujaku Dōchū 無着道忠 (1653–1745). It concludes that Zengaku was the basis for the development of Chanxue and Seonhak, in the sense of a modernized study of Chan and Seon that is partly informed by Western and international notions of religion, philosophy, science, psychology, and historical method.
