Bankei Yōtaku (盤珪永琢; 1622-1693) was a Japanese Rinzai Zen master, and the abbot of the Ryōmon-ji and Nyohō-ji. He was a major Zen figure of the Edo period and is best known for his emphasis on a minimalist sudden approach to Zen which simply relies on the unborn Buddha mind. He became well known in Japan for his public talks in colloquial Japanese which were popular among laypersons.

Bankei Yōtaku was born in 1622, in Harima Province to a samurai turned medicine man named Suga Dosetsu. His boyhood name was Muchi. Bankei's mother bore the last name of Noguchi, and little more is known of her, other than that the society of the time extolled her as 'Maya who begot three Buddhas,' - Maya being the mother of the historical Buddha, Shakyamuni. Bankei had four brothers and four sisters. His eldest brother, Masayasu, was a skilled physician and his second eldest brother was a practitioner of the Pure Land school of Buddhism. Hence Bankei's mother was likened to Maya, Masayasu to Yakushi - the Buddha of healing, his second eldest brother to the Buddha Amida, and Bankei himself to Shakyamuni Buddha. Bankei was a rebellious and mischievous child, though he showed remarkable intelligence. When Bankei was 11, his father died, and in the following year he entered school.

Here he was taught many of the Confucian texts. At this time, Bankei was young and full of questions and the Confucian classics he was being taught confused him greatly. One day, the teacher read the first line from 'Great Learning': "The way of great learning lies in clarifying bright virtue." Bankei entered a heated exchange with his teacher imploring them for the meaning of this. Bankei felt no satisfactory answers were given.

This gap in Bankei's understanding gave birth to many doubts and questions, and so he seized most every chance to question others on their knowledge. He would implore Confucian and Buddhist scholars and attend various religious gatherings in search of answers. All of this, however, proved futile for him. He became so distraught in his need to find answers that school was no longer a priority for him, and in 1633 he was kicked out of his family home. A family friend, Yūkan Nakahori, allowed Bankei to stay in a hut nearby. Being a bit eccentric, Bankei etched into a slat of wood "Practice hermitage" and placed it outside of his little hut.

It is likely that Bankei began practicing Shin Buddhism during this time. It is known that when Bankei was 15 he trained at a Shingon temple, where he apparently gained some footing in sutra study. However, Bankei was not satisfied with the Shingon approach and left that following year. At 16 he walked from Hamada to Ako to see a Rinzai Zen priest named Umpo Zenjo at Zuiō-ji. Bankei wasted no time with Umpo and implored him on the meaning of bright virtue, to which Umpo advised the only path toward such understanding could be had through the practice of zazen. Bankei was intrigued by this advice and ordained as a monk at Zuiō-ji under Umpo. It was here he received his Buddhist name Yōtaku (meaning 'Long Polishing of the Mind Gem').

When Bankei turned 19 he left Zuiō-ji shortly after and travelled through Kyoto, Osaka and Kyūshū in search for an answer to his question. During his travels he would stay over at temples or sleep in the open wilderness, scrounging by as a beggar. In 1645, at age 24, Bankei returned to Zuiō-ji no wiser than the day he left. At this time Umpo informs him that the answer which he seeks can only be found within, not through an intermediary. Bankei left shortly after his return and built a hut nearby and lived as a hermit. He would sit for hours practicing zazen. He had given up bodily comfort and had no other goal during this time aside from coming to a complete understanding of things. He practiced this way for many years, but eventually the bodily neglect caused him to contract tuberculosis. He sought the counsel of a doctor who gave the prognosis of death.

It was during this near-death experience that Bankei realized the Unborn, later stating of the experience:

I felt a strange sensation in my throat. I spat against a wall. A mass of black phlegm large as a soapberry rolled down the side...Suddenly, just at that moment...I realized what it was that had escaped me until now: All things are perfectly resolved in the unborn.