Harada Roshi was a Soto Zen priest who was dissatisfied with his training in the Soto school. He wanted to experience the awakening that many great Zen masters wrote about, including Hakuin, Dogen, Rinzai and the Buddha himself. He turned, then, to the Rinzai school of Zen and began training at Sogen-ji and later at Nanzen-ji. It was at Nanzen-ji with the Rinzai master Dokutan Sosan Toyota Roshi (1840 - 1916) that Harada Roshi clarified the great matter of life and death. He received Inka Shomei (transmission in the Rinzai lineage) from Dokutan Roshi and, in turn, gave Inka Shomei to fourteen successors. 

Here, Harada Roshi recounts his awakening:

"I was able to hear ‘the sound of one hand clapping.’ That is to say that upon attaining kenshō, I really had deep peace of mind for the first time. As anyone who has had the experience knows, a very special joy accompanies that first kenshō, and in that joy I went off to myself and danced a little jig. But after a month or two, even that experience became doubtful, and I plunged into a deeper anguish than ever. Once again I threw myself into practice. Memories of things like sitting in the snow and doing zazen stark naked in a bamboo grove swarming with mosquitos come from this period. My second kenshō experience may sound a little distasteful. One morning while I was on a long begging trip, an old woman happened to urinate in the toilet beside a farmhouse gate as I passed. When I saw the frothing urine I had satori."

Yasutani Roshi was born into a poor family and worked as a Soto Zen Priest, traveling and giving lectures on Zen. But by the age of 40 he felt he was a fraud, and vowed to awaken to his true nature. He began attending retreats with Harada Sogaku Roshi and after two years came to awakening. Ten years later, at 52, he finished koan study, and at the age of 58 was given Inka Shomei by Harada Roshi. In 1954 he broke away from the Soto School and founded the Sanbo Kyodan, now Sanbo-Zen International. In the 1960s he made seven trips to the United States to lead intensive meditation retreats. It was during one of these trips that he met Taizan Maezumi Roshi who was acting as his translator. So impressed by Yasutani Roshi's talks, Maezumi Roshi requested to become his student and study with him. After completing the entire koan curriculum, Maezumi Roshi received Inka Shomei from Yasutani Roshi on 7 December 1970.

Koryu Roshi was a lay Rinzai teacher and successor of Joko Roshi who was originally a Shingon priest before studying Rinzai Zen. Joko Roshi's teacher, Muchaku Kaiko Roshi, was also originally a Shingon priest before studying koan of the Myoshin-ji line of Zen under Kazan Genku Roshi (1837 - 1917). Joko Roshi was a firm believer in lay practice and requested that Koryu Roshi not ordain.

In the 1930s, Joko Roshi gave Koryu Roshi the Tokyo Hannya Dojo to teach Zen, which he did for for over three decades. It was here in the late 1950s that the young Maezumi Roshi lived while he was at university and began to study koan with Koryu Roshi. After a long pause to complete the koan curriculum of Yasutani Roshi, Maezumi Roshi completed all the koans in Koryu Roshi's system and recieved Inka Shomei from him in 1973. 

Baian Hakujun Kuroda Roshi was head of the Soto Supreme Court and a leading figure of the Soto School. He was Maezumi Roshi's father.

Maezumi Roshi received Dharma transmission (Shiho) from his father in 1955 as well as Dharma Transmission (Inka) in two separate Rinzai lineages: first from Yasutani Roshi in 1970, and then from Osaka Roshi in 1973. 

Before moving to Los Angeles from Japan, he received degrees in Oriental Literature and Philosophy from Komazawa University and trained at Sojiji. In 1956, Maezumi Roshi went to Los Angeles as a priest at Zenshuji Temple, the Soto Headquarters of the United States.

He founded the Zen Center of Los Angeles in 1967 and left twelve successors before his untimely death in 1995.