Rion Yamashiro (山城 理音 Yamashiro Rion) is a class A player. She joined the karuta club of Fujisaki High School, and is the vice president of the club. She is also the granddaughter of Kyoko Yamashiro, a certified reader and Level 7 karuta player.
Rion has short red hair cut in pageboy style and pale brown eyes.
Rion appears to be a timid person who rarely shows emotions where she is actually a big eater and the main reason she plays karuta is the rice she is bribed with.
Rion is finely attuned to her grandmother's reading style. This leads her to prefer her grandmother's reading over other readers. She is fast, with agile and light hand movements. Unfortunately, she lacks stamina and motivation.
Rion and Chihaya faced against each other in the team finals for the National High School Karuta Championship. Rion did well against her at first, until she injured Chihaya by accident. After that, Rion's hesitation and Chiaya's burning desire to win gave Chihaya the edge to beat her.
Chihaya chooses chocolate as her go-to snack in between matches. Rion would rather eat onigiri. Their food choices have become a point of contention when Rion left her bento at home and Chihaya offered her chocolate to eat.
Rion is the vice president of Fujisaki Karuta Club, in which Yoshihiko is the president. Both seem to be on a good term, often encouraging each other and enter tournaments together. With Fujisaki's double leaders system, when one of them is in an easier match will take control as the leader in a team tournament. When Yoshihiko lost to Wataya Arata in High School National Individual Tournament, Rion consoled and encouraged him, with him closely paying attention to her match with the Queen after. When Rion says she plans to attend club's meetings in the fall due to her participating in the East Qualifier, he goes along with her plan, also planning to participate in the qualifier.
Makoto thinks that Rion is a strange girl because it's pretty rare for Rion to show her emotions. He harbors feelings for her, but tries not to let it show and Makoto thinks Rion is copying his hairstyle. However, as the story progress, it seems like she corresponds his feelings.
Midori is Fujisaki High School's karuta club advisor and coach. She allows Rion to play in the group final against Mizusawa High School rather than an A Class player.
Rion played Taichi in the final match of the individual tournament of Class B. Taichi ended up winning against her.
- The name Rion means "reason, logic" (理) (ri) and "sound" (音) (on).
- Rion's surname Yamashiro means "mountain, hill" (山) (yama) and "castle" (城) (shiro).
- Chihaya Ayase gives Rion the nickname "Yama-chan" during their match together (in her mind), because she couldn't remember her full name.
- In Chapter 94, Rion reveals why she's playing Karuta and she is also called 'master of rice' there.
- By Chapter 96, Rion makes it to Class A by being placed 2nd in two class B tournaments.
- Rion's big appetite is balanced by her high metabolic rate .