Kotofurunushi is one of Japanese specters that is introduced in "Hyakki Tsurezure Bukuro" (One hundred bags in idleness) which is a collection of specters illustrations by Sekien TORIYAMA, and it is Tsukumo-gami (gods to a variety of things) of koto (a long Japanese zither with thirteen strings).
琴古主（ことふるぬし）は、鳥山石燕による妖怪画集『百器徒然袋』にある日本の妖怪の一つで、琴の付喪神（器物が変化した妖怪）。