In Japanese prose materials of the Heian period, "mo no suso" (lit. kimono-of-bottom, the bottom of a kimono) was generally used, while "mo suso" did not appear until the middle ages. Among these materials, in the Kagero Nikki (Diary oft-fay-fly), the word "mo no suso" was used, a fact which raises a chronological problem of its composition. But this phenomenon resulted from the fact that "mo suso, which was in current use in the world of the tanka, was used in the form of quotations from the tanka.