加治木 ゆみ

Yumi is a third-year at Tsuruga Academy, and one of its Mahjong Club's key members. Originally very weak at mahjong, she wound up buying a book after a loss to Kanbara in her first year, which allowed her to get much better. While she doesn't have a special ability, she is able to recognize players' abilities and try to form a defense against them as evidenced by her match in the prefectural finals.

Yumi is a calculating and great leader. According to Kanbara, it was Yumi's weirdness that grabbed Momo's attention. It was also thanks to her planning that Tsuruga was able to make it to the championship round of the prefectural tournament. When Kanbara first met Yumi she thought she was a gloomy ice queen, but changed her opinion after they became friends.

Under her somewhat cold and distant exterior, Yumi has shown a more human, humble, and even insecure side. She hid her face when Kanbara even mentioned that Yumi entered Momo's classroom and screamed "I want you!" She has been shown joking and laughing with Momo, and even confided in her underclassman when Amae's abilities got the better of her, saying she thought that if Momo was their captain that they'd have done better.

She is a very skilled Mahjong player, able to not only hold her own against both Saki and Koromo but she was even able to counter the former; she was able to figure out Saki's strategy within two Hands and counter her perfectly. Whilst she herself deemed that one moment as pure luck, she is shown to be a strategic player. She, like Hisa, is also able to grasp concepts at a fast pace, picking up on subtle things that others wouldn't notice immediately.