清水佐紀 (Shimizu Saki) is a Japanese former idol, actress, model, and Hello! Project advisor. She is a former member of Hello! Project, having joined as a member of Hello! Project Kids in 2002 and later debuting as the leader of Berryz Koubou in 2004. During her time in Hello! Project she was also the leader of the Hello! Project Dance Club as well as a member of ZYX, High-King, BeriKyuu, Cat's♥Eye 7, and GREEN FIELDS. She graduated from Hello! Project on March 3, 2015 in a joint graduation concert with the other members of Berryz Koubou. Afterwards, Shimizu became a Hello! Project advisor and has been primarily involved in Hello Pro Kenshuusei rehearsals. She retired from the entertainment industry on November 30, 2021.