While still in art school, Ishizuka made short animated films mostly for herself, usually pairing them with music. Her film Gravitation ended up at the 2005 Tehran International Short Film Festival and grabbed attention from both NHK and Madhouse. NHK wanted her to direct a music video for Minna no Uta (Everyone's Songs), their long-running program designed to showcase independent animators and musicians. She'd already signed on as a production assistant at Madhouse though, and didn't feel comfortable taking outside work, so she declined. But NHK wasn't ready to let it go—they asked Madhouse directly if the studio would handle the project with Ishizuka directing. Madhouse said yes, and in 2004, Tsuki no Waltz (The Moon Waltz) became her first professional film.