In the letter to his uncle written in February 1615, in between Osaka Fuyu no Jin (the Siege of Osaka in Winter) and Osaka Natsu no Jin, and in letters to his older brother and sister, the name Nobushige is used.
大阪冬の陣と大阪夏の陣の半ばの慶長20年2月に叔父にあてた手紙や、兄・姉にあてた手紙にも信繁の名がある。