Arima Kousei
Kousei Arima
有馬 公生
Arima Kousei
 Gender Male
 Birthday March 28 (Aries)
 Age 15 (Main series)
16 (Coda)
 Status Alive
 Relatives Takahiko Arima (Father)
Saki Arima (Mother, deceased)
Hiroko Seto (Guardian)
 Occupation Pianist / Student
 Japanese Voice Natsuki Hanae
 English Voice Max Mittelman
 Manga Chapter 1
 Anime Episode 01: Monotone/Colorful

Kōsei Arima (有馬 公生 Arima Kōsei) is the main protagonist of the Shigatsu wa Kimi no Uso series. He is the son of Saki and Takahiko Arima, who attended Sumiya Junior High School, and was the youngest winner of the Maihou Piano Competition.


Kousei is a boy with black, short, messy hair, and dark blue eyes. He is most commonly seen wearing his school uniform, but is also seen wearing casual clothes as well. He also has an average height.


As a child, Kousei was calm and obedient. When he is not hanging out with Ryota Watari and Tsubaki Sawabe, Kaori Miyazono he spends most of his day alone in his thoughts. This dense characteristic makes him oblivious to what is going on around him. For instance, he does not notice the rivalry and resentment his fellow piano competitors had for him nor Tsubaki's crush on him. He also stares at Kaori for long, thinking how great of a person she is, which she misinterprets as him having perverted thoughts of her.

Kousei admires Kaori because she is opposite; he wishes to become more free-spirited like her. The closer Kousei and Kaori get, the more his feelings for her deepen and the more he opens up to other people. She helps him build his confidence and convinces him to perform again.


Kousei's ability was honed through the training by his mother which led to his achieving of technical perfection at a very young age.



Kousei became a pianist at the encouragement of his mother's friend, Hiroko Seto, after Kousei recreated an improvised song (“Idiot Husband”) that Hiroko was playing, in anger of her husband. Following a collapse in his mother's health, Kousei's style of learning to play the piano was drastically changed, As a result, Kousei started becoming distant from his friends and focused solely on perfecting his piano skills in an attempt to satisfy his mother and make her happy. However, he stopped playing after her passing. His mother's death resulted in his inability to hear the pieces he played. Following the death of his mother, he lived for two years without playing the piano and saw the world in monochrome.

One fateful spring day, Tsubaki had Kousei meet her and Watari in the park, to meet a girl who was claimed to be a fan of classical music. Kousei heard a tune being played on the melodica, and followed it to the park, where he saw a girl playing with young children. He took out his flip phone to photograph them, but due to a misunderstanding, the girl lashed out at him. When Tsubaki and Watari arrived, the former introduced the girl as Kaori, who, after finding out that she had, in fact, attacked the pianist, Kousei Arima, apologised immediately for her violent first impression.

Relationships Edit

Kaori Miyazono Edit

Though Kousei had never met Kaori before, Kaori and her parents had always admired him since they first saw him perform. Kaori took up playing the violin hoping to perform with Kousei one day. Throughout the series, they had many adventures in which Kousei slowly gained feelings for Kaori. Each adventure had Kousei realize the importance of himself as a musician, as well as learn more about Kaori and become closer to her, something which eventually flourished into romantic feelings. However, Kousei refused to confess as he was misled to believe that Kaori was in love with Watari. When Kaori collapsed on the day of the Gala Performance due to the sudden paralysis of her legs and received a concussion, Kousei started to doubt himself, seeing his Mom, Saki Arima, in Kaori as both of them has made a huge impact in Kousei's life, and asked him to play the piano. Kousei started to give up on music once again as he felt that music was the one who took away everything that was precious to him. However, after talking to Kaori about not giving up hope at the hospital, Kousei was touched by her words and decided to persevere once more in his last piano competition while Kaori was undergoing surgery. Unfortunately, Kaori was unable to pull through the surgery which led to her death, with her presumably dying on the operating table. Kousei received a letter from Kaori's parents which was written by Kaori before she underwent surgery. In the letter, Kaori expressed her love and gratitude towards Kousei and thanked him for bringing joy and meaning to her life. At the end Kaori wrote that she was in love with not Watari, but Kousei.

Tsubaki Sawabe Edit

Kousei and Tsubaki have been best friends since the day they were born, playing together and growing up incredibly close, being best friends as well as next door neighbors (with Tsubaki calling him her 'hopeless kid brother'). They go to the same middle school and are usually seen walking home together. Tsubaki at first denies that she likes Kousei, but after various stages of denial, she starts to secretly develop feelings and a crush towards him. She later on confesses to him indirectly about her feelings for him, something which Kousei (being the dense man he is) does not realize the meaning of. On the last episode of the anime, she was shown to be around Kousei, stating that she will not leave him alone and will follow him around like his guardian angel.

Ryota WatariEdit

Kousei and Watari have been friends since they grew up and played together a lot when they were kids. Girls like him and he likes girls. They go to the same junior high school and Watari is one of the few friends that Kousei can trust. Watari constantly gives advice to Kousei, backing him up when Kousei was feeling down. Watari was supposedly Kaori's love and constantly acts lovey-dovey with her which causes Kousei to be annoyed. When Kousei tells Watari that he is in love with Kaori, he gives an advice on how to get her to like him and gives Kousei the confidence he needs to visit the ill Kaori.

Nagi AizaEdit

Nagi is Takeshi's little sister. Despite being cheeky and devilish towards Kousei on occasion, she respected him as their friendship grow as they are hanging out more with each other and is encouraged by Kousei to learn a piece. Kousei acted as her tutor and Nagi agreed to take lessons from him every week and worked hard. It is later indirectly seen that Nagi develops a crush on Kousei.

Hiroko SetoEdit

Hiroko was the first one to find out that Kousei had perfect pitch and was a genius with the piano at a young age. Saki Arima interpreted this and decided to immediately give Kousei lessons and make him a world class pianist in her place. Later though, it is shown in her own flashback that she blamed herself for Kousei's suffering, saying that if she hadn't told Saki to turn Kousei into a pianist, he wouldn't suffer. Because of this, she decided that she couldn't meddle with Kousei's life anymore.

Emi IgawaEdit

After almost falling asleep from previous performances, Emi was instantly inspired by Kousei, whose performance lasted less than four minutes, as she recalled. When his performance reached its end, Emi bursted into tears. Emi put away all of her interests and hobbies, and focused on the one and only thing she needed to top Kousei: the piano. She grew up to be close with Kousei and Takeshi as they were always competing in piano competitions and locked the spots for top three. They have a mutual relationship but she and Takeshi are angered as Kousei kept winning first place in competitions. Takeshi claims that she is somewhat “in love” with Kousei, though she doesn’t exactly express it. It is said that she wanted Kousei to remember his true self.

Takeshi AizaEdit

Kousei has a similiar relationship with Takeshi to Emi with similiar reasons. Takeshi respected Kousei and named him his hero but insisted that he was always a step behind Kousei, which angered Takeshi. This made him frustrated and resulted in him practicing intensely every day, quitting soccer in order to practice and focus on playing piano, and later on, became a great pianist.


  • (To Tsubaki) "There's no one who'd ever fall in love with me."
  • (To himself) "If you can't hear the sound, then imagine it."
  • (To himself) "She moves me with such power like the pounding of my heart."
  • (To Saki, as a child) "All I wanted was to make you happy. Even when I wanted to play with Tsubaki and Watari, or when you hit me, I always put up with it and kept practicing. All I wanted was for you to get better! All I wanted was for you to be happy! And yet...I wish you would just die."[1]
  • (Monologuing about Kaori) “Will it reach her? I hope it reaches her.”[2]
  • (To Nagi) "Music might just transcend words."[3]
  • (To himself) "The spring where I met you. A spring...without you."[4]
  • (To Kaori) "I had you."[5]
  • (To Kaori) "I want to see you."[6]
  • (To Watari) "I... really like Miyazono."[7]
  • (To Hiroko) "I want to see that sight again with my own eyes one more time. That's what made me think...That I'd like to become a really weird pianist!"
  • (To himself) "I knew all along. The ghost of my mother was a shadow of my own creation. An excuse for me to run away. My own weakness. Mom isn't there anymore. Mom... is inside me."
  • (To Emi and Takeshi) "I have to play. Gotta play. 'Cause I... I made a promise."

Trivia Edit

  • Kousei is voiced by Konrad Bösherz in the German dub, and Jordi Naro in the Spanish dub.
  • Kousei might have a condition called Amusia or some form of it. Amusia is a brain condition that causes the afflicted person to be unable to hear a music's pitch.



  1. Anime: Episode 09: Resonance
  2. Anime: Episode 10: The Scenery I Shared With You
  3. Anime: Episode 17: Twilight
  4. Anime: Episode 22: Spring Wind
  5. Anime: Episode 11: Light of Life
  6. Anime: Episode 19: Goodbye, Hero
  7. Anime: Episode 20: Hand in Hand