From the early part of the Heian period into the 10th century, ONO was active as a calligrapher; he is credited with having cast aside the practice of using the Chinese style of calligraphy, which had been the convention up to then, and laying the foundation for the development of a Japanese school of calligraphy.
平安時代前期、10世紀に活動した能書家であり、それまでの中国的な書風から脱皮して和様書道の基礎を築いた人物と評されている。