A first-year high school student at Achiga Girls' Academy. In elementary school, she invited Nodoka to the "Achiga Children's Mahjong Club." She played with Nodoka from elementary school until the first year of middle school, and she reforms the Achiga Girls' Mahjong Club in order to meet Nodoka again after her transfer. She has a bright and active personality. B-cup chest. Her usual attire is a tracksuit.

A first-year high school student at Achiga Girls' Academy. In elementary school, she attended the same mahjong club as Shizuno and Nodoka. Afterward, she attended a different middle school with a mahjong club, but upon entering high school, she enrolls in Achiga Girls' Academy with Shizuno to meet Nodoka again. She is an intelligent girl capable of complex calculations. C-cup chest.

A second-year high school student at Achiga Girls' Academy. She attended the mahjong club with Shizuno, Ako, and Nodoka. Even after the club disbanded and everyone left, she maintained the club room alone for over two years. She has a bright personality and is a reliable presence when the team is in a pinch. Her mahjong skills are considerable, and she is "loved by the Dora." F-cup chest. Her family runs an inn called "Matsumikan."

A third-year high school student at Achiga Girls' Academy. Kuro's older sister. She is extremely sensitive to the cold and wears heavy clothing even in summer. She wanted to attend the "Achiga Children's Mahjong Club" with Shizuno and the others, but refrained because she was already a middle schooler at the time. Like Kuro, she possesses great mahjong skills. G-cup chest. Her family runs the inn "Matsumikan."

A second-year high school student at Achiga Girls' Academy. She has been playing mahjong against adults since kindergarten. She admires Harue Akado and quit mahjong when Harue retired from the front lines. She joins the mahjong club after being invited by Kuro and learning that Harue would become the coach. She treasures a necktie she received from Harue. B-cup chest.

An alumna of Achiga Girls' Academy and advisor to the mahjong club. During her college years, she ran the children's mahjong club at her alma mater, where Shizuno, Ako, Kuro, and Nodoka were her students. She was later scouted by Toshi Kumakura and joined a corporate team in Fukuoka. She was active in the corporate league, but the team disbanded shortly after due to the parent company's financial difficulties. Upon returning to her hometown, she learned that her former students had started a mahjong club and became their manager. C-cup chest.

A first-year student at Kiyosumi High School. She serves as the Vice-Captain in team matches. A recognized beauty within the story, she speaks politely to everyone but possesses a fairly blunt and strong-willed nature. A skilled player who won the individual division of the National Middle School Mahjong Tournament (Inter-Middle), her appearance and skill make her a focus of media attention. She was at Achiga until middle school. K-cup chest.

A first-year student at Kiyosumi High School. She performs miraculous mahjong feats (able to win rounds with a score of exactly plus-minus zero). A master of the Rinshan Kaihou move. Usually quiet, introverted, and timid. She has a kind heart for her friends and a hidden strength of character, displaying incredible concentration and competitive spirit during matches. B-cup chest.

A first-year student at Kiyosumi High School. In team matches, she is assigned as the Vanguard, partly because she doesn't have to worry about complex point calculations. A cheerful and always positive mood-maker for Kiyosumi. While she is a bit of a ditz who struggles even with elementary school math drills, she has a strong side and refuses to show tears in front of her classmates Saki and Nodoka when she feels frustrated. She is nearly invincible in East-only matches. Her favorite food is tacos. A-cup chest.