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The religious name of Kūkai, the founder of the esoteric Buddhist sect Shingon in the early Heian period of Japan, was Henjō Kongō. Henjō translates to "transformation and achievement," while Kongō pertains to "vajra" in the Sanskrit language. As an honorific title, the term denotes the pinnacle of religious accomplishments, symbolizing Kūkai's exceptional level of spiritual attainment within Shingon Buddhism.