Additionally, "Various Japanese Family Trees" ("New Compilation of Various Japanese Family Trees Analogy") says that 'a court lady of Jotomonin, a poet, Murasaki Shikibu, an author of The Tale of Genji, or Masatada's granddaughter, Tametoki's daughter, mistress of Michinaga, the chief adviser to the Emperor,' which clearly shows that she was a mistress of Michinaga, but the true relationship between them is unknown.
鎌倉時代の公家系譜の集大成である『尊卑分脈』（『新編纂図本朝尊卑分脉系譜雑類要集』）になると、「上東門院女房　歌人　紫式部是也　源氏物語作者　或本雅正女云々　為時妹也云々　御堂関白道長妾」と紫式部の項にはっきり道長妾との註記が付くようになるが、彼女と道長の関係は不明である。