Kabane (hereditary title) (カバネ)
Kabane refers to the titles given by Okimi (great king) (Yamato sovereignty) to powerful clans which showed ones' relationships to the sovereignty as well as ones' ranks in the Yamato sovereignty of ancient Japan.
It is unknown how they were originated. It is believed that they were given to powerful clans to show their ranks and official duties as they began solidifying their positions in relation to Royal Family when Yamato sovereignty became stable.
Kabane which denoted official duties included kuni no miyatsuko (the heads of local governments), Ataganushi (territorial ruler) and inagi. Kabane which denoted ranks, social statuses and positions included kimi, omi, muraji, miyatsuko, atai, obito, fuhito and suguri. Other kabane included konikishi which was given to the Royal Families of Baekje after fleeing to Japan due to the fall of their country.
After the Jinshin War (occurred in 672), the kabane system existed in name only when Yakusa no Kabane (the eight honorary titles) system was installed by the Emperor Tenmu, which put omi and muraji in sixth and seventh from the top, and thus those titles no longer held any values. Instead, those competent individuals who showed their loyalty to the emperor were given new kabane such as mahito, ason, sukune and imiki. However, almost all clans were granted the kabane ason after Nara period, and therefore Yakusa no Kabane system also lost its meaning and existed in name only.
It was believed that the kabane were given to each clan from the beginning of Yamato sovereignty; however, based on the research of historical records, some strongly suggest that they were given to individuals in the beginning of Yamato sovereignty. It is highly likely that the latter theory is correct.
However, even if it was the case, Emperor Tenmu (Yamato sovereignty) had to create the Yakusa no Kabane system which resulted in the dysfunction of the original kabane system since the kabane were given to too many people, and uji and kabane became integrated through heredity as the system of clans and hereditary titles based on a ritsuryo legal code remained simply as a form. Furthermore, the fact remains that Emperor Tenmu introduced new kabane such as mahito, ason, sukune and imiki rather than using the ones that had already been passed on, that he allowed only the members of an immediate Imperial Family to be in the position of Ujinokami which had the right to give kabane, and that he even had the authority to give permission in the beginning.
Also, this Yakusa no Kabane system stopped functioning like the original kabane system after the death of Emperor Tenmu.
The only kabane that remained from the Yamato sovereignty till the Meiji Restoration were ason and sukune; Nagatoshi from Fujiwara clan (Masujiro OMURA), FUJIWARA no Ason Toshimichi (Toshimichi OKUBO), Shigenobu from Sugawara clan (Shigenobu OKUMA) and Aritomo from Minamoto clan (Aritomo YAMAGATA) being the examples of ason, and 'Hirobumi from Ochi clan' (Hirobumi ITO) being the example of sukune. Whether those names were true or not, it is said that uji and kabane were only used since it was necessary when serving the emperor and the Imperial Court.
The use of traditional uji including 'Fujiwara' and kabane including 'ason' was banned and finished its role when the Meiji Government was able to unify the 'uji = family name' by issuing the order to allow all commoners to have family names in 1870 and the compilation of Jinshin-koseki (family registries in Jinshin) in 1872. Since the Jinshin-koseki, the traditional kabane as well as uji were replaced with 'uji = family name' due to a legal basis. This new name system was established among all Japanese citizens when the order issued in 1875 made it mandatory for all commoners to have family names.