The Otomo Clan (大伴氏)
The Otomo clan was one of the dominant clans in ancient Japan. Its kabane (hereditary title) was 'Muraji,' but upon the institution of Yakusa no Kabane, the clan was renamed 'Sukune' (third highest hereditary title). It is said that the clan descended from Ameno Oshihi-no-Mikoto, who served as a guide in Tensonkorin (the descent to Earth of the grandson of the Sun Goddess) and had a kindred relationship with the Saeki clan (the Saeki clan was generally regarded as a branch family of the Otomo clan, though some say the opposite is true).
Summary
As the word "Otomo" is said to mean "Grand Tomonomiyatsuko" (the chief of various departments at the Imperial Court), the Otomo clan presumably controlled various other clans. The Otomo clan was also in charge of military affairs, together with the Mononobe clan. The difference between these two military clans, the Otomo and the Mononobe, can be likened to bodyguards versus the national army, respectively. Otomo clan members mainly served as what are now called "guardsmen" or "the Imperial Guard."
The Golden Age of the Otomo Clan
The Otomo clan extended its influence in the late 5th century, during the age of OTOMO no Muroya and the reign of Emperor Yuryaku, reaching the height of its prosperity when OTOMO no Kanamura--the grandson of Muroya--became Oomuraji in the reign of Emperor Buretsu. Kanamura was credited with the reception of Emperor Keitai, was appointed to govern Mimana, and was serving as Oomuraji during the reigns of 5 different emperors--Emperors Buretsu, Keitai, Ankan, Senka and Kinmei but, upon being ousted from power on the accusation of ceding 4 prefectures within Minama to Kudara in the reign of Kinmei, he hid himself in his home in Sumiyoshi County, Settsu Province (present-day Tedzukayama, Sumiyoshi Ward, Osaka City). After that incident, the era of conflict between the Soga clan and the Mononobe clan began.
(The late Jyugo KUROIWA claimed that Kanamura was brought down after his involvement in the succession conflict between Kinmei and the other two Emperors of Senka and Ankan who disputed his coronation.)
From the Asuka Period to the Nara Period
Despite conflict, the Otomo clan maintained its influence, and OTOMO no Nagatoko was promoted to Udaijin (Minister of the Right) after the Taika Reforms in the Asuka Period. In the Jinshin War of 672, OTOMO no Maguta and OTOMO no Fukei, who were the brothers of Nagatoko, commanded the army with distinction, after which the Otomo clan produced Dainagon (Chief Councilors of State), Chunagon (Vice Councilors of State), and Sangi (Councilors) within the political world until the Nara Period.
The Otomo clan also produced several kajins (waka poets), such as OTOMO no Yasumaro, OTOMO no Tabito, OTOMO no Yakamochi, and OTOMO no Sakanouenoiratsume. OTOMO no Komaro was sent on the Kentoshi route and smuggled the Buddhist monk Ganjin (Jianzhen) into Japan.
Political Strife and Decline
The Nara Period was marked by political strife in which the Otomo clan was often involved and in Nagayao no Hen (the Conspiracy of Nagayao), Tabito, who was close to Nagayao, was temporarily transferred to Dazaifu as punishment, while in TACHIBANA no Naramaro no Hen (the Conspiracy of TACHIBANA no Moroe, which involved the son of TACHIBANA no Moroe), Komoro was tortured to death and OTOMO no Kojihi was deported, not to return until after the demise of the Emperor Shotoku. OTOMO no Yakamochi was not involved in either incident, although he was allegedly involved in the assassination plot of FUJIWARA no Nakamaro and was transferred as punishment. Then, after Emperor Kanmu, who was not a descendant of Emperor Tenmu's imperial line (Emperor Tenmu was enthroned after the Jinshin War), was enthroned, Yakamochi was transferred again under suspicion of involvement in HIKAMI no Kawatsugu's War. He was promoted to Chunagon in 783, but Emperor Kanmu moved the capital and established Nagaoka Kyo the following year. The Otomo clan, displeased by the relocation of the capital, assassinated FUJIWARA no Tanetsugu, who had led the project. As a consequence, OTOMO no Tsuguhito (son of Komaro and alleged mastermind) was condemned to death, and Yakamochi, who had died just before the incident, was excommunicated. In addition, OTOMO no Kunimichi (the son of Tsuguto) and OTOMO no Naganushi (the son of Yakamochi) were exiled.
However, even in spite of these incidents, the Otomo Clan did not entirely lose its power: OTOMO no Otomaro was appointed as the first Seii Taishogun (literally, "great general who subdues the barbarians") and sent to defeat the Emishi (natives of the North, also called the Ezo), along with SAKANOUE no Tamuramaro in the early Heian period and in late 803, Kunimichi returned to the capital with an imperial amnesty and was promoted to Sangi. In 823 of his later years, the Otomo clan changed its name to "Tomo" to avoid using the name of Emperor Junna (Imperial Prince Otomo).
TOMO no Yoshio, son of Kunimichi, began to distinguish himself in politics in the days of Emperor Seiwa, and a Dainagon (Chief Councilor of State) was chosen from the Otomo clan in 864 for the first time in years. However, it was revealed that he was involved in the Otenmon Incident that plotted to oust MINAMOTO no Makoto in 886, and he was exiled to Izu Province.
(The theory that the Fujiwara clan plotted this conspiracy to expel other clans from the imperial court is widely accepted.)
This incident dealt a strong blow to the Tomo clan, which had, until then, survived so many political conflicts and kept the reputation as a venerable noble family.
Aftermath
In 939, 72-year-old TOMO no Yasuhira was promoted to Sangi, becoming the first Kugyo (high court noble) from the clan in some time, though no Kugyo was chosen from the Tomo clan upon his retirement in 950. In the early Heian period, the Tomo clan, like the Ki clan, was considered to be the clan that carried the ancient practices of warriors, but as the samurai gained power, the Tomo clan's political influence faded, and after TOMO no Tadakuni became the first Shinto priest of Tsurugaoka Hachiman-gu Shrine, the bloodline was inherited, as the job was passed on through generations. Some clans still remain in the various locations they settled down after they were appointed to Zuryo (provincial governor) and changed to these groups of warriors.