Ason (朝臣, Ason, Asomi) was a hereditary noble title in Japan, used mainly between Asuka and Heian periods. At first, it was the second highest, below Mahito, which was given to members of the Imperial family, but after Heian period it became the highest of the eight noble titles:[1] Ason, Mahito, Sukune, Imiki, Michinoshi, Omi, Muraji, and Inagi.[2]