The eldest son of Riemon SOGA (the founder of a business), Riemon Tomomochi (Tomomochi SUMITOMO) was adopted by the Sumitomo Family, which turned out to be an encounter of the Sumitomo Family with copper.
そして蘇我理右衛門（業祖）の長子理兵衛友以（住友友以）を養子に迎えたことが、住友家と銅との出会いであった。