Koun Ejō was initially a disciple of the short-lived Darumashū sect of Japanese Zen under Nōnin

Nōnin

was a Japanese Buddhist monk who introduced the concept of Zen to Japan. He did not receive any formal dharma transmission, but invented his own teachings, which he called the "Japan Bodhidharma School", or Darumashū. Later, he dispatched one of his disciples to China to receive a letter of...

, but later studied and received dharma transmission

Dharma transmission

Dharma transmission refers to "the manner in which the teaching, or Dharma, is passed from a Zen master to their disciple and heir...

 under Dōgen

Dogen

Dōgen Zenji was a Japanese Zen Buddhist teacher born in Kyōto, and the founder of the Sōtō school of Zen in Japan after travelling to China and training under the Chinese Caodong lineage there...

 and is considered his spiritual successor by the Sōtō

Soto

Sōtō Zen , or is, with Rinzai and Ōbaku, one of the three most populous sects of Zen in Japanese Buddhism.The Sōtō sect was first established as the Caodong sect during the Tang Dynasty in China by Dongshan Liangjie in the 9th century, which Dōgen Zenji then brought to Japan in the 13th century...

 school. His transmission is the final koan chronicled in the Denkoroku

Denkoroku

, written by Keizan Jokin Zenji in 1300, is a kōan collection of 53 enlightenment stories based on the traditional legendary accounts of the Zen transmission between successive masters and disciples in the Sōtō Zen Buddhist lineage from Shakyamuni Buddha to Japanese Zen Master Ejō, a first...

. He is also the author of the , a collection of informal talks by Dōgen which Ejō recorded throughout his discipleship. After Dōgen died, Ejō struggled to maintain leadership of the new Eiheiji monastery, due in part to his lack of training in China that prevented him from completing the temple as a Chinese-style meditation hall, as well as unfamiliarity with Chinese-style monastic practices.

He gave dharma transmission to Jakuen

Jakuen

Jìyuán , better known to Buddhist scholars by his Japanese name Jakuen, was a Chinese Zen monk and a disciple of Rujing. Most of his life is known to us only through medieval hagiography, legends, and sectarian works. It is generally agreed, though, that during his time at Tiāntóng Mountain he...

, Gikai, Gien and Giin, but did not resolve power disputes among them, leading to the sandai sōron

Sandai soron

The sandai sōron , or third-generation differentiation, was a dispute over the orthodoxy and succession of Sōtō Zen Buddhism. The major figures involved were Jakuen, Gikai, Gien, and Giin, all of whom claimed the right to serve as abbot of Eihei-ji...

that temporarily split the community.