In addition, in another theory Yoshinobu who became an adopted son of Yoshimune was not this Yoshinobu but MINAMOTO no Yoshinobu, who was the first son of MINAMOTO no Yoshichika, Yoshimune's brother, and this is more rational with respect to their ages.
また、義宗の猶子となった義信は、この義信ではなく、義宗の弟源義親の長男の源義信であるとする説もあり、年齢的にはこちらのほうが辻褄が合う。