Script error Mayumi Muroyama (室山まゆみ Muroyama Mayumi?) is the joint penname of Japanese manga artists Mayumi Muroyama (室山真弓?, born 1955-08-30) and her younger sister Mariko Muroyama (室山真里子?, born 1957-09-27). They made their professional debut in 1976 with Ganbare Aneko in Shoujo Comic.
In 1977, Muroyama began publishing the long-running Asari-chan, which is collected in 76 volumes and which has sold 26,500,000 volumes total as of May 2006, making it the seventh best-selling shōjo manga ever in Japan. Asari-chan received the 1986 Shogakukan Manga Award for children's manga. Several of Muroyama's manga have been adapted as anime, including Asari-chan as both a television series and theatrical movie, Dororonpa! as a television series, and Mr. Pen Pen as a television special.