Although the works are unsigned, as a postscript, in the latter part of the Heian period, FUJIWARA no Sadanobu, who had long worked as an appraiser of calligraphical works (and was a noted calligrapher in his own right), authenticated the calligraphy as being penned by Michikaze at the age of 35, giving credence to the works' authenticity.
署名はないがその奥書きに、平安時代末期の能書家で鑑識に長じていた藤原定信が、道風35歳の書であることを考証しているので、真蹟として確実である。