Furthermore, since the "Hyakki Yagyo Emaki" (a picture scroll of the demons' night parade drawn in the Muromachi period, which was before Sekien's time) contains a drawing of a biwa specter, there is a theory that Sekien drew 'Biwabokuboku', which is introduced in the "Hyakki Tsurezure Bukuro", based on the "Hyakki Yagyo Emaki."
また、石燕より以前、古くは室町時代の『百鬼夜行絵巻』に琵琶の妖怪が描かれていることから、石燕は『百鬼夜行絵巻』をもとに『百器徒然袋』の琵琶牧々を描いたとの説もある。