At first, he was separated from his mother who remarried into the Okudaira clan, therefore, he referred to himself as Tozo SUGANUMA as the adoptive heir of the younger brother of his mother, and had an opportunity to serve Ieyasu TOKUGAWA.
当初、奥平氏に再嫁する母とは離別させられたため、母の弟の養嗣子として菅沼藤蔵を名乗り、家康に仕える機会を得た。