The Soga clan is believed to have been founded by
Soga no Ishikawa, son of
Takenouchi no Sukune and great-grandson of
Emperor Kōgen.
Toraijin theory Due to the clan's heavy influence from the mainland, specifically to that of Korea, scholars have theorized that the clan might have been founded by immigrants (
Toraijins). The founder of the Soga clan,
Soga no Ishikawa's father,
Takenouchi no Sukune is also suspected to be a Toraijin as he had many descendants who were associated with clans that had close relationships with Korea such as the Soga clan and the
Hata clan (through his son
Hata no Yashiro). Takenouchi no Sukune's name appears multiple times in Korean records and was heavily associated in
Silla–
Wa affairs at the time. He is best known for serving as Grand Minister (Ōomi) to the Regent
Empress Jingū, who descended from
Amenohiboko, a prince from Silla.
Alexander Vovin, a linguist specialising in East Asian languages also stated that the Soga clan members likely had Korean origin. Linguistically, he posited that the name "Soga" was in fact a combination of Korean words: "So" from "
Sor", an ancient Korea word for
metal, and "Ga" from "
-kan", a suffix that was used as titles for royal and high nobility in Silla that may have roots in the Central Asian word "
Khan". This would result in "Sor-kan", but since
Western Old Japanese (WOJ) did not include final consonants, "So[r]ka[n]" ultimately became "Soka" and later "Soga". The significance of metal is also evident in Seorabeol's representative Chinese characters, "金城" meaning "city of gold (or metal)". In essence, Soga clan's heavy hints of Silla influence are also represented by the Hata clan, another Silla-originating clan that also descend from Takenouchi no Sukune, someone that was integral to
Silla–Wa affairs and an individual who Vovin also suspects of being Korean. Another indication arises from the names of the members themselves. Names such as "
Soga no Karako (蘇我韓子)", meaning "Korean person of Soga" and his son, "
Soga no Koma (蘇我高麗)", meaning "
Goguryeo person of Soga" all allude to possible Korean origins. It is also said in the
Fusō Ryakuki that a hundred members of the Soga clan (under
Soga no Umako) wore
Baekje clothing and were entertaining guests. Despite the compelling evidence, the current consensus in regards to the origin of the Soga clan does not point to a Toraijin origin, only predicating that the Soga clan members were heavily invested in foreign affairs, thus naturally having many connections to Korea. However, this conclusion is constantly being scrutinized and is also subject to change with future excavations. ==Notation==