After entering Showa period, Tadachika KUWATA, a scholar of Japanese history, pointed out that the signature in Kita no mandokoro's autograph letters was only a hiragana character of 'Ne', and advocated the theory that her name was originally 'Ne' and usually called as 'O-ne' with a prefix 'o', and 'Nene' was an error in writing in 'Taikoki', etc.
昭和に入って日本史学者の桑田忠親が北政所の自筆消息（手紙）の自署が「ね」一文字であることを理由に彼女の名は本来は「ね」（通称では接頭辞「於（お）」をつけて「おね」）であり、「ねね」は「太閤記」などによる誤記であるという説を唱えた。