Ayaka Nishiwaki (Nishiwaki Ayaka), nicknamed a~chan (stylized as a-chan), is a Japanese singer and dancer. She is known as one of the members of the Japanese electropop group Perfume. Nishiwaki was born and raised in Hiroshima, Japan, where she attended Actor's School Hiroshima with friends and current Perfume members Yuka Kashino and Ayano Omoto. She formed Perfume in 2000 with Kashino and former member Yuka Kawashima, who left shortly after to focus on her schoolwork. After discussing the issue with her mother, who believed that a three-piece group had more stage presence than a duo, Nishiwaki asked Omoto to join the group. Her younger sister Sayaka is a member of the group "9nine". In March 2011, Nishiwaki graduated from Asia University with a degree in economics.