Soga clan

A powerful clan from Yamato Province to the Asuka period. Their surname was Omi. Later genealogies claim that the clan's ancestors were Takeuchi no Sukune, the grandson (or great-grandson) of Emperor Kōgen, along with the Hata, Kose, Heguri, Ki, and Katsuragi clans, and that the clan began with Takeuchi no Sukune's son, Ishikawa no Sukune. There are two theories about the clan's origin: either in Soga, Kashihara City, Nara Prefecture, or in the Ishikawa River basin in Minamikawachi County, Osaka Prefecture. Another popular theory is that the clan originated when Mokumachi, a high-ranking official from Baekje, came to Japan at the end of the 5th century and settled in Soga, Yamato. The name Soga is also written as Soga, Munega, Kogi, Koga, etc.

In the late 5th century, during the reign of Emperor Yuryaku, there is a legend in the Kogoshui that Manchi was in charge of the Three Treasuries of the Imperial Court and was involved in its finances, and in the Nihon Shoki there is an article about Karako's activities in relations with Silla, but from the mid-6th century, when Iname became minister, the clan's influence rapidly expanded. During this time, it expanded its base south along the Soga River, then east from the foot of Mount Unebi, reaching all the way to Asuka, and in the 7th century, it placed its main clans at key transportation points. In other words, the Kitashihime family was placed in the Shinaga Valley in Kawachi, the Oane no Kimi family to the south of Mt. Miwa, the Sakaibe no Omi family to the west of Asuka, the Kurayamada Ishikawa no Omi family on the Yamada road, and finally the Kamimiya royal family of Prince Umayado (Prince Shotoku) in Ikaruga, which controlled the Tatsuta road. Under these powerful families were placed the Kume, Sakurai, Tanaka and other branches, forming a complex clan structure supported by the Aya clan of Yamato, which had come from overseas.

Thus, during the time of Umako in the early 7th century, the Soga clan completely dominated the political world and promoted the establishment of a unified ancient state. However, during the reigns of Emishi (Ezo) and Kurashukuri (Iruka), opposition from other clans intensified, the clan's unity was disrupted, and the main family was finally wiped out in June 645. Three other clan members subsequently held the position of minister in the political world (Ishikawa no Omi Maro, Murajiko, and Akae), but the Soga clan was wiped out in the aftermath of the Jinshin War (672). After that, the Soga clan was succeeded by a descendant of Murajiko who became the Ishikawa clan.

[Teiji Kadowaki]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

大和国家(やまとこっか)から飛鳥(あすか)時代にわたる有力氏族。姓(かばね)は臣(おみ)。後世の系図では、孝元天皇(こうげんてんのう)の孫（または曽孫(そうそん)）の武内宿禰(たけしうちのすくね)を、波多(はた)・巨勢(こせ)・平群(へぐり)・紀・葛城(かずらき)氏とともに祖先とし、武内宿禰の子の石川宿禰に始まるとする。その起源は、奈良県橿原(かしはら)市曽我(そが)または大阪府南河内(みなみかわち)郡の石川流域とする両説があったが、百済(くだら)の高級官人木満致(もくまち)が5世紀末に渡来し、大和の曽我に定着したのに発したとの説も有力である。氏名の蘇我は、曽我、宗賀、巷宜、巷哥などとも記される。

　5世紀末葉の雄略(ゆうりゃく)朝に、満智(まち)が朝廷の三蔵(みつくら)をつかさどって財政に関与した伝承が『古語拾遺(こごしゅうい)』にみえ、『日本書紀』には韓子(からこ)が対新羅(しらぎ)関係で活躍した記事がみえるが、6世紀中葉の稲目(いなめ)が大臣になったころから勢力を急速に伸ばした。この間に、その基盤を曽我川沿いに南にさかのぼって拡大し、ついで畝傍山麓(うねびさんろく)から東に向かい飛鳥にまで達し、7世紀には主要な諸家を交通の要点に配した。つまり、堅塩媛(きたしひめ)家を河内磯長(しなが)谷に、小姉君(おあねのきみ)家を三輪山南方に、境部臣(さかいべのおみ)家を飛鳥の西方に、倉山田石川臣家を山田道に、最後に竜田道(たつたみち)を抑える斑鳩(いかるが)に厩戸皇子(うまやどのおうじ)（聖徳太子）の上宮王家を配した。これら有力諸家の下に久米(くめ)・桜井・田中氏らの諸支族を配し、渡来系の東漢(やまとのあや)氏諸族に支えられる複合的な氏族構造を形成した。

　こうして7世紀初頭の馬子(うまこ)の時代には、完全に政界を主導し、統一的な古代国家の体制を推し進めた。しかし毛人(えみし)（蝦夷）、鞍作(くらつくり)（入鹿(いるか)）の執政期になると、他氏の反発が強まり、一族の結束も乱れ、ついに本宗家は645年6月に滅んだ。一族からはその後も政界に3人の大臣（石川臣麻呂(まろ)、連子(むらじこ)、赤兄(あかえ)）がたったが、壬申(じんしん)の乱（672）の戦後処理によって蘇我氏は滅んだ。以後、蘇我氏の後は連子の流れが石川氏として継承した。

［門脇禎二］

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