Kukai is one of the towering figures of Japanese religious and cultural history, honoured by the posthumous title Kobo Daishi, "the Great Master who Spread the Dharma." Dissatisfied with the Buddhism available in Japan, he travelled to Tang China in 804, was initiated at the capital into the full transmission of esoteric (Vajrayana) Buddhism, and returned to found the Shingon ("True Word") school. Its teaching centres on the cosmic Buddha Mahavairocana and holds that enlightenment can be attained "in this very body" (sokushin jobutsu) through the ritual integration of body, speech, and mind, the making of mudras (gestures), the chanting of mantras, and the visualization of mandalas. He established the great monastic complex on Mount Koya, still the school's centre and the site of his mausoleum, where tradition holds he remains in eternal meditation.
Beyond religion his influence on Japanese civilization is immense: he is credited (traditionally) with the invention of the kana syllabary, celebrated as a master calligrapher and poet, and founded a school open to commoners. Popular devotion made him the object of one of Japan's great pilgrimages, the eighty-eight-temple circuit of Shikoku.