TV-Series
Description
Arata Sagimori is a second-year student at Achiga Girls' Academy and a key protagonist in the series. She serves as the vice-captain of the school's mahjong team and is appointed as the club's president by the coach, Harue Akado, owing to her level-headed and reliable nature.

Her background is deeply connected to the game of mahjong and her admiration for Harue Akado. From a young age, Arata was skilled enough to play mahjong with adults, often at the inn run by the family of her childhood friends, the Matsumi sisters. She was a devoted fan of Harue, who was then the star player of Achiga's legendary team. Arata's enthusiasm for the game was so profound that she treasures a necktie given to her by Harue as a substitute for an autograph, a keepsake she continues to wear. However, she became deeply disillusioned and stopped playing mahjong altogether after Harue's team suffered a significant loss in the national semifinals and subsequently quit the game herself. For a time, Arata held onto a sense of disappointment, not only with mahjong but with her idol's perceived failure. It is only when she learns that Harue has started playing again and has returned to Achiga as a coach that Arata reconsiders her stance, eventually becoming the final member to join the newly formed mahjong club.

In terms of personality, Arata is characterized as a cool and composed individual who often serves as the most stable and responsible member of the group. This dependability is precisely why Harue entrusts her with the role of club president, noting that she is someone who can be counted on to look the part. Despite her outward calm, she is driven by a strong personal motivation. Her actions are largely fueled by her deep-seated admiration for Harue. Playing mahjong again is not merely about competition; it is a way for Arata to reconnect with her hero and perhaps come to terms with the past. This is poignantly illustrated before her match in the national tournament, where she tells Harue that the necktie is the reason she is there and that she intends to wear it all the way to the finals. She is also a childhood friend of Kuro and Yuu Matsumi, and her family runs a local bowling alley, a detail that heavily influences her playing style.

Arata's role in the story is that of a steadfast pillar for the Achiga team. As the vice-captain, she plays in the critical second half of team matches. Her journey involves overcoming her past trauma associated with Harue's loss and rediscovering her own love for the game. Throughout the story, she develops from a former player who had quit in disappointment into a formidable competitor determined to lead her team to the national stage, carrying on the legacy that Harue left behind. Her development includes a rigorous training period under Harue, where she hones her unique skills and learns to adapt her style to become a more versatile and unpredictable player.

Arata's most notable ability is her unconventional and old-fashioned mahjong style, which is heavily inspired by both Harue Akado and her family's business. She is known for creating complex, multi-sided tile waits that are modeled after the patterns of pins left standing after the first roll in bowling, such as formations known as the Big Five, Washout, or Dime Store. Her signature waits primarily focus on the pinzu (dots) suit, though she is not limited to them. To complement this, she adopts strategic elements from Harue's playbook, which involve exploiting gaps in opponents' defenses by using honor tiles for safe discards and setting her winning waits on those same tiles. During matches, she wears a bowling glove to promote her family's business, a visual hallmark of her unique approach to the game. Her style is initially described as outdated, as if she had not played for years, but through training, she evolves it, combining her natural bowling-pin waits with a more strategic and deceptive overall game.