Michishige Sayumi, born July 13, 1989 in Ube, Yamaguchi Prefecture, Japan, is a 6th generation member of the J-pop group Morning Musume and has the third longest tenure of any member in the group (behind Niigaki Risa and Takahashi Ai and tied with Tanaka Reina).
She joined Morning Musume in 2003 along with KameiEri, Fujimoto Miki and Tanaka Reina, which all made their debuts with Morning Musume in the group's 19th single, "Shabondama". In 2005 she was assigned as mentor to 7th generation member Kusumi Koharu, until Kusumi's graduation in December 2009.
Michishige was also a member of the Hello! Project unit Ecomoni, along with former Morning Musume member Ishikawa Rika.
When Michishige passed the audition to join Morning Musume, Tsunku, Morning Musume's producer, commented that her singing was weak. After the audition, Michishige took voice lessons to improve her singing, but even she admits that her own singing is still bad.
She portrays an extremely narcissistic image of herself in TV shows, often calling herself the cutest member in Morning Musume and saying that her cuteness overwhelms her bad singing voice. In one of the skits known as Hello! Morning Theatre on their variety show, Hello! Morning, she frequently played a character known as "Ichiban Kawaii" (Cutest).