As the Keicho era began, there appeared new setsuyoshu based on 47 characters of the iroha syllabary including 'ゐ' (wi), 'ゑ' (we) and 'を' (wo) instead of the former 44 iroha characters, following Teika Kanazukai (the distinction of using Kana in the same pronunciation) presented in the section of 'Imi Moji no koto' (嫌文字事, Awful things regarding characters) in "Gekanshu" written by FUJIWARA no Teika (also known as FUJIWARA no Sadaie).
しかし慶長年間に入ると、藤原定家の『下官集』「嫌文字事」で示された定家仮名遣に従って、いろは44文字は「ゐゑお」を含む47文字とする節用集が登場した。