Exoteric and Esoteric Buddhism – Kūkai

gate gate pāragate pārasaṃgate bodhi svāhā

“Kūkai (空海; 27 July 774 – 22 April 835), born Saeki no Mao (佐伯眞魚), posthumously called Kōbō Daishi (弘法大師, “The Grand Master who Propagated the Dharma”), was a Japanese Buddhist monk, calligrapher, and poet who founded the esoteric Shingon school of Buddhism. He travelled to China, where he studied Tangmi (Chinese Vajrayana Buddhism) under the monk Huiguo. Upon returning to Japan, he founded Shingon—the Japanese branch of Vajrayana Buddhism. With the blessing of several Emperors, Kūkai was able to preach Shingon teachings and found Shingon temples. Like other influential monks, Kūkai oversaw public works and constructions. Mount Kōya was chosen by him as a holy site, and he spent his later years there until his death in 835 C.E.

Because of his importance in Japanese Buddhism, Kūkai is associated with many stories and legends. One such legend attribute the invention of the kana syllabary to Kūkai, with which the Japanese language is written to this day (in combination with kanji), as well as the Iroha poem, which helped to standardise and popularise kana.

Shingon followers usually refer to Kūkai by the honorific title of Odaishi-sama (お大師様, “The Grand Master”), and the religious name of Henjō Kongō (遍照金剛, “Vajra Shining in All Directions”).”

This above from Wikipedia