At the end of the Nara period manyo-gana was developed through slight transformations of the characters, with characters with fewer strokes being increasingly used, and during the Heian period they were further developed into characters with extremely simplified figures (known as soryaku) or characters with some strokes partly omitted (known as shokaku) which could be written faster and more efficiently.
万葉仮名は、奈良時代の終末には、字形を少し崩して、画数も少ない文字が多用されるようになり、平安時代に至るとますますその傾向が強まり、少しでも速く、また効率よく文字が書けるようにと、字形を極端に簡略化（草略）したり字画を省略（省画）したりするようになった。