Shiromi Kosegawa

Shiromi Kosegawa (小瀬川 白望 Kosegawa Shiromi) is a third year at Miyamori Girls' High.

Appearance
Shiromi has white hair and black eyes with a dot in the middle.

She wears the standard Miyamori uniform with a vest instead of a jacket.

Personality
Shiromi is a stoic, quiet and apathetic girl who is very tactical during her matches, contrasting her incredibly lazy attitude outside of them. While waiting for her turn, she has a habit of leaning all the way back in her chair. Whenever she starts contemplating on something, she likes to either bite her finger or put one her hands over an eye.

Despite her apathetic exterior, Shiromi is very warmhearted and fond of her friends, offering them support and comfort when needed.

National Tournament Arc
Shiromi is introduced during the first match of the second round against Himematsu, Eisui and Kiyosumi. During the first few hands of her match she tries risky discards to disrupt Yuuki Kataoka, but finds out it has no effect. When Yuuki claims she will make sure the second round doesn't happen, Shiromi doubts her and calls her annoying. She then begins to worry about her hand and Komaki Jindai. When Jindai awakes and announces that she has been asleep and will play her best, Shiromi says that she doesn't like troublesome ones. Both her and Yuuki start to play cautiously after Komaki has woken up, thinking that something big is going to happen. Suzu Ueshige wins off of Komaki though, making Shiromi question what was going on. The next play when Yuuki declares riichi to try to finish the match off, Shiromi finally gets a win. During the final hand, Komaki finally taps into her ability and wins off of Yuuki, making Miyamori end up in first.

After the match, Shiromi is still in the playing area when Aislinn Wishart arrives. Shiromi asks her to carry her back but to no avail. In the waiting room Kurumi sits on her lap watching the match. She asks Sae if she can go home because Aislinn would win, but was denied. When she notices Mako Someya's weird play asks about her school. When Ailsinn's match ends she tries to comfort her by saying that will feel even more tired if she cries and begs her not to cry. Shiromi is again seen at halftime of Kurumi's match, where Kurumi Kakura again sits on her lap "charging herself". She makes an appearance in Sae's flashback of how the team formed. Here she is seen alone in the clubroom until Sae walks in. After noting how rare it was for her to be sitting at a table, Shiromi says its only because she got bored of standing. When the new teacher arrives (Toshi Kumakura), she participates in a match and is then beaten badly by her. We next see Shiromi standing over an unconscious but waking Sae. She asks if she's okay, then gets embarrassed when Sae thanks her for worrying. After walking her back to the playing area she tells Sae to "hang in there". Shiromi next appears during the captain's match, reminding herself how no one was a match for Toyone Anetai when they first played. Shiromi is then seen in a flashback. Here she declines to eat with some of her classmates because she feels sluggish. When she leans back in her seat she notices the new transfer student Aislinn Wishart. Her stomach then growls causing Aislinn to feed her.

After Kurumi and Sae call her to meet the new mahjong player, Shiromi invites Aislinn to join them. With everyone together, Toshi introduces them to Toyone and gets the Mahjong players to have a match with her. After she defeats the girls and says she has to leave, Shiromi asks her when she is changing schools and that the club would welcome her anytime. Later in the captain's match, Kurumi thinks Toyone is going to get another victory, but Shiromi informs her that Saki Miyanaga can still call another kan before the girl wins the hand with a rinshan kaihou.

After the match, she and the rest of the team welcome back Toyone. When Kasumi Iwato and Komaki Jindai arrive to give Toyone her autograph, she shows interest in going to the beach.

Final Eight Arc
Shiromi is present with the rest of her team trying out their swimsuits.

Playing Style/Abilities
Shiromi's ability is based on the legend of Mayoiga, 迷い家, which takes place on Mt. Shiromi (白見山 Shiromi-san) in the Iwate prefecture. Mayoiga is the Lost's House, an old japanese-style manor only lost people can find. With a enormous black gate, a red and white flowers garden, animals like chickens, cows, horses, and other kinds. The house contains endless amounts of rooms. It's is said those rooms contained various kinds of items and riches. Also the things of the house, even the animals or flowers, can make a lost traveler blessed with good fortune; however, not picking a thing is also an option that could bless the traveler too. If so, the traveler may find in a river an item from this very Mayoiga or Lost's House. The blessing only affects not selfish and greedy lost travelers. It's a manor between the boundaries of the real world and other planes of existence.

When Shiromi has doubts for any reason, it directly causes her hand to become more expensive. She tends to slowly build her hand without opening it or calling riichi, leading to a distinctive play style. Shiromi is tactful when it comes to her opponents hands and has solid defense. She often discards what others call risky tiles, but it hasn't been shown to backfire on her.

Etymology

 * The name Shiromi means "white" (白) (shiro) and "wise, desire, hope" (望) (mi).
 * Shiromi's surname Kosegawa means "small" (小) (ko), "swift current, rapids" (瀬) (se) and "river, stream" (川) (kawa/gawa).

Trivia

 * The Mayoi 迷い in Mayoiga 迷い家, not only means to lose one's way, but also to be doubtful or hesitant. Shiromi uses the legend almost literally: the more she hesitates and thinks, the more expensive her hand becomes.
 * Her ability was only briefly explained in the manga, and then expanded upon (adding in Mayoiga to the explanation) in the anime.