Birushana-butsu was a Buddha teacher who had been taught in the Kegon-kyo (Avatamsaka Sutra; a body of Buddhist scriptures which were formed in Central Asia before and after 400 A.D., and it was brought to Japan via China), and was described as the head of a religious sect of 'the Lotus Matrix World' by the Kegon-kyo.
盧舎那仏は、華厳経（西暦400年前後に中央アジアで成立し、中国経由で日本へもたらされた仏教経典）に説かれる仏で、華厳経に言う「蓮華蔵世界」の教主である。