He studied the Yuishiki theory (of vijnapti matrata, the theory that everything exists only in the mind) of the Hosso sect with Taiki, a priest of Daian-ji Temple in Nara, and in 807 took Buddhist vows, receiving the succession ritual from Kukai in 810.
奈良大安寺の泰基に法相・唯識を学び、807年（大同(日本)2年）に受戒、810年（弘仁元年）には空海から灌頂を受けた。