He was born into the Mibu (壬生) family in present-day Tochigi Prefecture, Japan and entered the Buddhist priesthood at Enryaku-ji on Mt.

The journal describes an account of the workings of the government of China, which saw strong and able administrative control of the state and its provinces, even at a time of a supposed decline of the Tang dynasty.

[4] Initially, he studied under two masters and then spent some time at Wutaishan (五臺山; Japanese: Godaisan), a mountain range famous for its numerous Buddhist temples in Shanxi Province in China.

Later he went to Chang'an (Japanese: Chōan), then the capital of China, where he was ordained into both mandala rituals: the Mahāvairocana-sūtra and the Vajraśekhara-sūtra,[5] along with initiation and training in the Susiddhikara Sūtra tantra.

[7] In 847 he returned to Japan and in 854, he became the third abbot of the Tendai sect at Enryakuji, where he built buildings to store the sutras and religious instruments he brought back from China.