According to the records, after his father, Yoshinaka, was killed by Tamehisa ISHIDA in Awazu, Omi Province, and also his older brother, MINAMOTO no Yoshitaka (Shimizu no Kanja), by the Hojo clan, his mother, Tomoe Gozen, is said to have given birth to Yoshimune in her home town of Shinano Province, and hid herself with the baby deep in the mountains in Kiso fukushima Town, Shinsyu.
それによると、父・義仲が近江国粟津で石田為久に討たれた後に、兄・源義高(清水冠者)が北条氏に殺害されると、母・巴御前は郷里・信濃国で義宗を出産したとされ、信州木曽福島町の山奥に身を潜めたという。