He was born in 1551 as a son of Kazumasa SOGO, a younger brother of Nagayoshi MIYOSHI (there is another theory which says that the year of his birth was 1549).
天文(元号)20年（1551年）、三好長慶の弟・十河一存の子として生まれる（生年は天文18年（1549年）ともいわれる）。