Soga Clan (蘇我氏)

Soga clan (Soga no uji) was a shizoku (clan) which ruled between the Kofun (tumulus) and Asuka periods (6th - 7th centuries). The Soga clan's kabane (hereditary title) was Omi, and it was an influential local family whose members successively served as ministers over several generations.


Soga is inscribed as "蘇我" in the "Nihonshoki" (Chronicles of Japan). It was alternatively recorded as "宗我" in the "Sendai Kujihongi" (Ancient Japanese History): Lineage of the Mononobe and Soga clans, "Jogu Shotoku Hooteisetsu" (Biography of Shotoku Taishi), and "Nihon Sandai Jitsuroku" (Veritable Records of Three Reigns of Japan). It was written as "巷奇" in "The Origin of Gango-ji Temple."


According to "Kojiki" (The Records of Ancient Matters) and "Nihonshoki" (Chronicles of Japan), the Soga clan descended from TAKESHIUCHI no Sukune who achieved great success in the Sankan Seibatsu (Punitive Expeditions Against the Three Korean Kingdoms) led by Empress Jingu. However, the specific accounts were not recorded until SOGA no Iname appeared in the mid-6th century, and events before that remain largely unknown.

One theory states that Soga clan was a powerful family that was a native to the area around Kawachi Province by Ishikawa River (present-day Ishikawa River basin in Osaka Prefecture; some even identify the precise location as Ichisuka Kanan-cho, Minamikawachi-gun), or Soga no Sato, Katsuragi Prefecture (present-day Soga-cho, Kashihara City, Nara Prefecture). Yet, another theory (based on tracing lineage) suggests that the Soga clan descended from the migrant clans from Kudara (Baekje; one of three kingdoms on the Korean Peninsula) and settled there; however, these theories are yet to be verified. The "Shinsen Shojiroku" (Newly Compiled Register of Clan Names and Titles of Nobility) classifies Soga clan as Kobetsu (clan descended from successive emperors).

Regardless of the origins of the Soga clan, its deep ties with migrant clans is without-doubt, immigrants to ancient Japan; and it is thought that the rise of the Soga clan was aided by the relatively advanced technologies introduced to Japan by Shinabe (technicians in offices) who were toraijin (settlers), who became subjects to royal authority as indentured professionals. Additionally, it is widely assumed that the Soga clan was the first to adopt Buddhism when it was introduced to Japan during the Asuka period. This is conjectured to have been carried out by the Soga clan for the purpose of countering the Mononobe and Nakatomi clans that were appointed to perform Saishi (religious rites and services) in the Chotei (Imperial Court).

The Soga clan is thought to have ruled over an area covering present-day Takaichi-gun, Nara Prefecture by the latter half of the sixth century. The Soga clan's rise to power is signified in the construction of several imperial palaces in Asuka after they seized power.

Height of Prosperity
The Katsuragi and Heguri clans, whose members served as ministers in the past, had lost their respective influence by Iname's generation due to the demise of the main branches of their clans. Soga clan became one of three major powers alongside the Muraji Otomo and Mononobe clans; after OTOMO no Kanamura was overthrown, the Mononobe (MONONOBE no Okoshi) clan Omuraji (Official post in ancient Japan.) and the minister SOGA no Iname remained as the two major powers. Soga also followed the precedent set by the Katsuragi and Fujiwara clans by marrying off his daughters SOGA no Kitashihime and Oane no Kimi to Emperor Kinmei, and established himself as a maternal relative of the imperial family.
(It is speculated that the Soga clan became one of the noble families from which the Emperor's wives were chosen by virtue of their blood ties and the fact that Umako's primary residence (Ubusuna) was in Katsuragi-ken, and Iname's wife was also from Katsuragi.)

The political structure characterized by the dominance of two major houses was inherited by SOGA no Umako after the deaths of Iname in 570 and Emperor Kinmei in 571; However, a conflict over succession erupted after Emperor Yomei's death. The Soga clan assassinated Anahobe no Miko who was supported by the Mononobe clan, despite the fact that Anahobe no Miko was the son of (SOGA no) Oane no Kimi, and defeated MONONOBE no Moriya in the battle. After this event, the Soga clan members monopolized appointments to Omuraji, and governance became unipolarized under their dominance.

The abuse of power under three generations of the Soga clan can be gleaned from events such as the assassination of Emperor Sushun by SOGA no Umako, the demand for the ceding of Katsuragi-ken from Empress Suiko, neglect of the throne by SOGA no Emishi, and the coup against Jogu Ooke (Prince Yamashiro no oe) by SOGA no Iruka, and the overthrow of SAKAIBE no Marise.

However, there are also those who view Iruka's hard-line politics as having been motivated by his desire to overcome the weakness of a political base undermined by antipathy among the Imperial family and other influential families towards the Soga clan after the death of SOGA no Umako. This refutes the negative portrayals of the Soga clan found in historical records such as the "Nihonshoki."

The power of the Soga clan was significantly diminished by a coup (Isshi Incident, which takes its name from the Zodiacal name of the year the incident occurred and can alternatively called the "Incident of 645.") led by Emperor Tenchi in 645, in which Iruka was assassinated and Emishi prompted to commit suicide.

From the Taika Reforms to the Jinshin Rebellion. The political turmoil merely signified the decimation of the main branch of the Soga clan whose members were direct descendents of Emishi. SOGANOKURA-YAMADA no Ishikawamaro, a child of SOGA no Kuramaro (Emishi's younger brother) from the branch family of Soga, conspired with Naka no Oe no Oji in the coup. Later, Ishikawamaro was appointed to Udaijin (Minister of the right) and arranged to marry off his daughters Ochi no Iratsume and Mei no Iratsume to Naka no Oe no Oji.
Ishikawamaro himself was prompted to commit suicide when he was falsely charged in 649, and his younger brother, SOGA no Himuka, whose accusations led to his Ishikawamaro's death was demoted and transferred to Dazaifu (It is speculated that SOGA no Himuka was transferred as a means to keep him silenced.)
However, Ishikawamaro's other brothers SOGA no Akae and SOGA no Murajiko were respectively appointed as Minister of the Left and Minister of the Right (Although the veracity of Murajiko's appointment is less certain.) during the reign of Emperor Tenchi, and the Soga clan maintained a certain degree of status.

Murajiko died before Emperor Tenchi was officially enthroned, and Akae and his other younger brother SOGA no Hatayasu both of whom took the side of Emperor Kobun during the Jinshin War were respectively deported and prompted to commit suicide upon their defeat. SOGA no Yasumaro, a nephew of Akae and the son of Murajiko was trusted by Emperor Tenmu to the extent that he was entrusted the succession of the Soga clan and was bestowed the family name ISHIKAWA Ason (second highest of eight hereditary titles). Kuramaro's sons remained in the center of politics even after the Isshi Incident, and maintained Murajiko's lineage even as their influence was whittled down through successive political struggles.

ISHIKAWA Ason of Soga's Lineage
ISHIKAWA Ason of Soga lineage produced Empress Jito and Empress Genmei who assumed the throne from the late Nara period through to the Asuka period (both Empress Jito and Empress Genmei were the daughters of Ishikawamaro and were respectively mothered by Ochi no Iratsume and Mei no Iratsume.)

However, several unfortunate incidents befell the throne: Princess Yamanobe no Himemiko, a sotomago (grandchild from a daughter married into another family) of SOGA no Akae followed her husband Imperial Prince Otsu to the grave when he was eliminated by Empress Jito, and ISHIKAWA no Tone no Iratsume, the wife of the late Emperor Monmu, was stripped of her rank due to infidelity and her children Hironari no Oji and Hiroyo no Oji were stripped of their standing as members of the Imperial family by association. The Tone no Iratsume's incident is allegedly a conspiracy hatched by FUJIWARA no Fuhito and his wife Agata no INUKAI no Michiyo to eliminate rivals and ensure the enthronement of Prince Obito, who was Fuhito's half brother born from a different mother.

According to "Manyoshu" (the oldest anthology of tanka), Imperial Prince Hozumi, a sotomago of Akae, was accused of adultery with Tajima no Himemiko and demoted. Imperial Prince Hozumi was fortunate enough to have climbed the ranks to Daijo-daijin (Grand Minister) after Empress Jito's death; however, he died young.

Fuhito's legal wife was SOGA no Masako who was Yasumaro's daughter (and the mother of FUJIWARA no Muchimaro, FUJIWARA no Fusasaki, and FUJIWARA no Umakai). Yasumaro's younger brother ISHIKAWA no Iwatari and his son ISHIKAWA no Toshitari became associated with the Southern House of the Fujiwara clan which was directly descended from Muchimaro by virtue of Masako's marriage to Fuhito. Toshitari served as Daihitsu (senior assistant president) to the Shibi chudai (the office handled the principal Empress Komyo's affairs) which was established by FUJIWARA no Nakamaro (the second son of Muchimaro), and barely maintained his standing as a middle class nobility.

However, as the Southern House of the Fujiwara clan entered a terminal decline after FUJIWARA no Nakamaro's Rebellion, the Ishikawa clan also failed to produce other kugyo (court noble) succeeding ISHIKAWA no Mamori (Toshitari's grandchild and the seventh generation of Umako's grandchildren), who was Shoshiinojo (Senior Fourth Rank, Upper Grade) and sangi (Councillor), died after the transfer of the capital to the Heian-kyo, and would vanish from history. Soga clan's lineage continues to the present day through the maternal line of SOGA no Masako who married FUJIWARA no Fuhito and gave birth to three sons: FUJIWARA no Muchimaro, FUJIWARA no Fusasaki, and FUJIWARA no Umakai. Incidentally, the only other person who introduced Soga clan blood to the Imperial line was SOGA no Iname's daughter SOGA no Kitashihime. The lineage is as follows: SOGA no Kitashihime, Sakurai no Oji, Kibitsuhime Okimi, Empress Kogyoku, Emperor Tenchi, and the present emperor.

The Theory concerning the Migrant Origins of the Soga clan. The theory concerning the migrant origins of the Soga clan' took academic circles by storm when it was first proposed by Teiji KADOWAKI in 1971, and became widely popular among ancient history buffs. Yasutami SUZUKI and Yukihisa YAMAO both supported Kadowaki's assertion that the Baekje high official Machi MOKU, who is said to have arrived during the reign of Emperor Ojin, is one and the same individual as SOGA no Machi; but, as Kenkichi KATO and Yoshitane SAKAMOTO have pointed out, there are many historical discrepancies and little evidence to prove the migrant origins of the Soga clan.

As the issues listed below reveal, it is impossible to prove that SOGA no Machi and Machi MOKU were the same person.

Whereas the name 'Machi MOKU' appears in the "Nihonshoki" in 294 during the Emperor Ojin's reign, it is quoted in the historical interpretation as 414; Furthermore, 'Machi MOKURA' appears in the History of Baekje of the "Samguk Sagi" (History of the Three Kingdoms) in 475, pointing to the chronological inconsistencies between the respective sources. It is unlikely that Machi MOKU, a member of a well regarded clan in Baekje, would forsake his family name and introduce himself as Soga clan. Influential migrant clans in ancient Japan only began voluntarily changing their places of origin from the eighth century. The inscription in the "Samguk Sagi" describing Machi MOKURA as having 'travelled south' does not indicate that he travelled to Wakoku (Japan). Machi MOKU was from a prestigious clan in Baekje; however, his grandchild's name was Goryeo which referred to the kingdom of Goguryeo.

Machi named his child "Karako," (means Korean) and Karako, in turn, named his own child, who would later father Iname, "Koma" (means Goryeo), both of which are distinctly exotic names. Their exotic names are one of the factors that gave cause to 'the theory of the migrant origins of the Soga clan'; but, as Chiaki MIZUTANI explains, the theory's wide appeal was also underlined by its conformity to historical perception of the Soga clans anti-establishment alignment. Furthermore, "Karako" as it is inscribed in the September 531 entry of the "Nihonshoki" refers to a 'child born of union between a Japanese man and a woman from a neighboring country'; since Karako is a common term used to describe people of mixed Wa (Japanese) and Korean descent, it is hard to believe that it specified any individual.

TAKENOUCHI no Sukune was previously alleged to be a fiction created by subsequent generations, and there are also those who view Soganoishikawa no Sukune to be a creation of descendents of the Ishikawa clan.

Recent Studies

On November 13th, 2005, the Nara National Research Institute for Cultural Properties announced it had been excavating remnants of what is believe to be the "Valley Palace Gate" of SOGA no Iruka's residence at Amakashi no Oka Toroku Site; archeologists expect their findings to verify inscriptions in the "Nihonshoki."