It ranked below Shosanmi (Senior Third Rank) and above Shoshii (Senior Fourth Rank) (Shoshiinojo (Senior Fourth Rank, Upper Grade)). Under the Ritsuryo system (a system of centralized government based on the ritsuryo code), those ranked Ninsangi and Jusanmi or higher were called kugyo (court noble). In case of posthumous honor, it was called Zojusanmi (posthumous Jusanmi).
Under the ritsuryo system, Jusanmi or higher ranks were called "ki" (literally, noble) or star ranks, and were court ranks for senior kizoku (noble). When contrasted with kunto (Order of Merit), it corresponds to Kunnito (Order of Second Class), and those with Shoshiinojo Sangi (councilor) and Jusanmi or higher court ranks were considered kugyo or kandachime (court noble).
Under the ritsuryo system, those with ranks Shoshiinojo Sangi, Jusanmi, or higher added 'Ason' (second highest of the eight hereditary titles) under their family names and a title of honor, 'kyo,' was added under their first names (imina (real name)), while those who served as a minister were given a title of honor, 'ko.'
Instead, those who were Jushii (Junior Fourth Rank) or higher, but not a kugyo, added 'Ason' under their family names and imina. Additionally, when a kugyo ranking Sanmi or higher died, the term kokyo was used, as was the case with the imperial family, to describe their death.
Furthermore, in later years, they were referred to as 'Sanmi-dono' or 'Sanmi-sama.'
In addition, those ranking Sanmi or higher were allowed to establish a mandokoro (administrative division of a high-rank family) as an agency for the household, and had Shikiji Jusanmi Karei (butler), Shoshoinoge Shikiji Sanmi Keshori as keishi (personnel in charge of household affairs).
In kani soto (corresponding relationship between court ranks of government officials and government posts), the corresponding government officials for Jusanmi are Dazai no sochi (Governor-General of the Dazai-fu offices, danjoin (President of the Board of Censors), Chunagon (Vice-councilor of state), left and right Konoe-Daisho (commander of the inner palace guard division), etc., but in reality, the Imperial Prince often served as the Dazai no sochi, Konoe-Daisho was routinely doubled by the Sadaijin (minister of the left) and Udaijin (minister of the right), and those with Sanmi often became left or right Konoe-Chujo (lieutenant general of the inner palace guard division). Therefore, those who serve as Chujo despite being Sanmi were called Sanmi-Chujo (Third Rank assistant director).
In the Heian period, until TAIRA no Kiyomori became the first samurai to become kugyo, the highest rank for both Seiwa-Genji (Minamoto clan) and Kanmu-Heishi (Taira clan) was Shoshii. Thus, when MINAMOTO no Yorimasa of Settsu-Genji (Minamoto clan), who had become a tributary of the Minamoto clan at that time, became the first from the Minamoto clan to be promoted to Jusanmi, after the Taira family were granted Sanmi and higher ranks, it was considered exceptional and was referred to as Genzanmi.
From the Muromachi period onward, the rank of Jusanmi was granted to successive generations of members of the Ashikaga Shogunate and the Kamakura Shogunate, as well as to Yoshishige SHIBA and Yoshitoshi SHIBA of the Shiba clan, members of whom held the position of kanrei (deputy to shogun). Additionally, Mochikuni HATAKEYAMA who supported the shogunate as kanrei was also promoted to Jusanmi, and there are cases of the rank being granted to powerful members of the Ashikaga family. Furthermore, in the late Muromachi period, Masanori AKAMATSU, a powerful Shugo (provincial constable), was granted the rank, and gradually, dominant daimyo (feudal lord) other than the Ashikaga clan began to be granted the rank. In particular, appointment of the rank from the beginning to the middle of the Sengoku Period (Period of Warring States) includes Yoshioki OUCHI who prospered as kanreidai (deputy kanrei), Motonobu TAKEDA of Wakasa Province, and Yoshisuke ITO of Hyuga Province. Among daimyo other than tenkabito (person becoming the ruler of the country) and their families, Jusanmi was the highest rank, but Yoshitaka OUCHI was promoted from Jusanmi to Junii (Junior Second Rank), and with time, there were more cases going beyond Jusanmi. Nobunaga ODA, who later becomes Udaijin also at one time held this rank, and his eldest son Nobutada ODA's rank was Jusanmi Sakone no chujo (Middle Captain of the Left Division of Inner Palace Guards). After Hideyoshi TOYOTOMI, who became the first Kanpaku (chief advisor to the Emperor) from a samurai family, conquered the country, samurai were increasingly promoted to high ranks, and Sanmi was granted to the clan and daimyo such as Kagemasa UESUGI and Terumoto MORI. Under the Edo bakufu (Japanese feudal government headed by a shogun), the inheriting grandson of the seii taishogun (literally, "great general who subdues the barbarians"), Tokugawa gosanke (three privileged branches of Tokugawa family), the gosankyo (three Tokugawa clan families who separated from the clan), and the lord of Kaga Domain who wedded the daughter of the Shogun were granted the rank.
In modern days, Jusanmi corresponds to Shishaku (viscount) in shakui (the rank of nobility), and ranks granted to bukekazoku (samurai families from the Edo period becoming nobles in the Meiji period) who had many Shishaku were notable. In the ranks for military personnel, it corresponded to Army General. Today, it is commonly granted posthumously to persons who made similar achievements as former Diet members, prefectural governors, or scholars who received conferment of the Kunnito (Order of Second Class).