In "Myohoji-ki," he is described as "Mr. Yasaburo GUNNAI joined the Yokoire (flanking attack)," and this description of joining the flanking attack is often used as a base of the theory that the separate troops existed actually.
『妙法寺記』に「郡内弥三郎殿は（中略）よこいれを成され候ひて」とあり、よこいれ＝側面攻撃をしたと言う記録が別働隊説の根拠とされることが多い。