He pointed out the possibility that it was missed or intentionally removed during the copying stage because Naoejo with the postscript came out from around the Tokugawa clan, saying that "I would like to accept the existence of 'Naoejo' with the condition that 'they were not the phrases of that time'" while paying attention to the postscript with 'a possibility that it was forged and inserted in later years', which also pointed out by Kazuhiko KASAYA.
『「当時のままの字句」ではないという条件付きで、「直江状」の存在を容認したい』とし、追而書については笠谷和比古も指摘した「後代の偽作挿入の可能性」に留意しつつも、追而書のある直江状が徳川氏周辺から出ていることから、筆写の段階で欠落または意図的に削除された可能性を指摘している。