Gasan Jōseki was a Japanese

Japanese people

The are an ethnic group originating in the Japanese archipelago and are the predominant ethnic group of Japan. Worldwide, approximately 130 million people are of Japanese descent; of these, approximately 127 million are residents of Japan. People of Japanese ancestry who live in other countries...

 Soto Zen master. He was a disciple of Keizan Jokin, and his disciples included Bassui Tokushō

Bassui Tokusho

was a Rinzai Zen Master born in modern day Kanagawa Prefecture who had trained with Sōtō, Rinzai and Ch'an masters of his time. Bassui was unhappy with the state of Zen practice in Japan during his time, so he set out in life with the mission of revitalizing it. The problems he saw were really two...

, Taigen Sōshin

Taigen Soshin

Taigen Sōshin was a Sōtō Zen monk. He received dharma transmission from Gasan Jōseki and is considered a patriarch by the Sōtō school....

, Tsūgen Jakurei, Mutan Sokan, Daisetsu Sōrei, and Jippō Ryōshū.

An alleged conversation of Gasan's was integrated into the famous American collection 101 Zen Stories

101 Zen Stories

101 Zen Stories is a 1919 compilation of Zen koans including 19th and early 20th century anecdotes compiled by Nyogen Senzaki, and a translation of Shasekishū, written in the 13th century by Japanese Zen master Mujū . The book was reprinted by Paul Reps as part of Zen Flesh, Zen Bones...

:

A university student while visiting Gasan asked him: "Have you even read the Christian Bible?"

"No, read it to me," said Gasan.

The student opened the Bible

Bible

The Bible refers to any one of the collections of the primary religious texts of Judaism and Christianity. There is no common version of the Bible, as the individual books , their contents and their order vary among denominations...

 and read from St. Matthew: "And why take ye thought for raiment? Consider the lilies of the field, how they grow. They toil not, neither do they spin, and yet I say unto you that even Solomon in all his glory was not arrayed like one of these...Take therefore no thought for the morrow, for the morrow shall take thought for the things of itself."

Gasan said: "Whoever uttered those words I consider an enlightened man."

The student continued reading: "Ask and it shall be given you, seek and ye shall find, knock and it shall be opened unto you. For everyone that asketh receiveth, and he that seeketh findeth, and to him that knocketh, it shall be opened."

Gasan remarked: "That is excellent. Whoever said that is not far from Buddhahood."

Although given the fact that Christianity was not introduced in Japan until significantly after Gasan's death, this story is likely apocryphal. Another explanation is that the story in Zen Flesh, Zen Bones writes "Gasan" but means Gisan Zenkai

Gisan Zenkai

Gisan Zenkai was a Zen Master in 19th century Japan. He taught in Okiyama. The most famous story about him concerns his conversation in 1837 with the disciple cooling his bath: this is given in an abbreviated version in Zen Flesh, Zen Bones, and in more expanded version in other sources...

, a 19th century Zen Master. Different editions of Zen Flesh, Zen Bones show the Gisan/Gasan mixup, a 19th century figure would make the story more plausible.