Hyakunin Isshu (one hundred waka poems by one hundred poets) is believed to begin with 98 decorative waka which had been selected by Sadaie as fusumae (images drawn on fusuma sliding door) when Yoritsuna lived in his villa in Kyoto, Ogura villa.
百人一首は京の別荘小倉山荘に住まった折に、定家に選定してもらった和歌98首をその襖絵として飾ったことに始まるといわれている。