[1] According to Teiji Kadowaki (門脇禎二) [ja] at Kyoto University, the name "Yamatonoaya" was widely used by Korean immigrants to apply dominance in their newly found home.

[4][full citation needed] Modern Japanese historians theorized that Yamatonoaya clan and its founder Achi no omi, originated from the Gaya confederacy, specifically from the kingdom of "Aya (安邪国)" (old name for Ara Gaya) where the placename became the etymology of the Aya clans.

According to Japanese scholars, Wani and Achi no omi founded Kawachinoaya and Yamatonoaya clan respectively, both being of Baekje origin and influential ethnic Koreans in Japan at the time.

They shared the same character "Aya" but separated one another with the use of cardinal directions ("Kawachi/西" meaning West and "Yamato/東" meaning East) as Wani's Kawachinoaya clan resided in "Furuichikoori (河内国古市郡)", (present day Furuichigun (古市郡) [ja] in Osaka) located in the west of Japan, while Achi no omi and his Yamatonoaya clan resided in the Yamato Kingdom found in the east.

[14][15] There were also heavily militarized, often guarding and protecting high-ranking members of the Soga clan[16][full citation needed] who also had deep connections with the Korean peninsula, specifically the kingdom of Baekje.