After 1261, Sengaku obtained many books such as Matsudono-gohon, Shosho-zenmon-shinkan-bon, Motonaga-Chunagon-bon, Rokujoke-bon, Tadasada-gohon, Sakeicho-bon and further devoted himself to the examination of Manyoshu and producing textbooks.
弘長元年（1261年）以降、松殿御本、尚書禅門真観本、基長中納言本、六條家本、忠定御本、左京兆本などを入手し、万葉集の校合・校本作成にさらにいそしむ。