HAKUIN (1686–1769), more fully Hakuin Ekaku, was a mid-Tokugawa period (1603–1868) reviver of Rinzai Zen. Hakuin was born to a commoner family in Hara, present-day Shizuoka prefecture. Entering Buddhism at an early age, he studied widely both Buddhist canonical works and Zen literature. He was also well versed in the secular literature of China and Japan, and in popular Japanese poetry and song. At age twenty-two he set out on his studies, visiting a succession of Zen masters and practicing meditation at various temples. At twenty-four he visited the Zen master Shōju Rōjin (Dōkyō Etan, 1643–1721), and after an arduous eight-month stay, was granted his teacher's sanction. For the next eight years Hakuin traveled to various temples, perfecting his understanding of Zen, eventually returning to his temple, the Shōinji in Hara, in 1718. Here he concentrated on teaching a considerable number of disciples. Hakuin also devoted much time...