Sō’ō ［相応］ (831–918): A priest of the Tendai school in Japan. He studied under Jikaku, the third chief priest of Enryaku-ji, the head temple of the Tendai school on Mount Hiei. He is said to have excelled in the performance of the esoteric prayer rituals. In 865 he founded Mudō-ji temple on Mount Hiei, in which a statue of the wisdom king Immovable was enshrined. In 866 he petitioned Emperor Seiwa to grant the title “great teacher” to Dengyō and Jikaku. This was the first instance of the title “great teacher” being bestowed in Japan. Sō’ō is also regarded as the founder of the Tendai practice of visiting the assigned shrines and halls on Mount Hiei every day for one thousand days (known as kaihō-gyō, “making a round on the mountain”).