7nin Matsuri (７人祭; "7 Person Festival") was one of three special "shuffle units" from Hello! Project in the summer of 2001. The shuffle theme was "summer festivals" and they had a reggae dance song. They released only one single, "Summer Reggae! Rainbow" (サマーれげぇ！レインボー) which included their version of a c/w song that was shared by all three shuffles. True to their name, they had seven members selected from Morning Musume (Mari Yaguchi and Maki Goto) Read more on Last.fm