Kiyosumi High School, located in Nagano Prefecture, is the focus school in the Saki manga and its anime adaptation. It is also the primary rival of Achiga Girls' Academy in the spin-off manga Saki Achiga-hen episode of side-A and its anime adaptation.
Kiyosumi's mahjong club was re-started by Hisa Takei two years ago and she was its lone member until Mako Someya joined the following year. After an influx of freshmen, led by Saki Miyanagaand Nodoka Haramura, the club enters its first mahjong tournament. After winning the Nagano Prefecture qualification tournament, Kiyosumi becomes the prefecture's representative at the 71st Inter High championships in Tokyo. They were a relatively unknown club prior to their success.