Diamond no Ace Wiki
Okumura Koushuu
Seidou High School - No. 20
Bats: Right Throws: Right
Kanji 奥村 光舟
Nickname Wolf Boy (狼小僧 Ōkami Kozō) (by Sawamura Eijun)
Gender Male
Age 15 (debut)
Date of birth 20 February
Place of birth Kanagawa
Education 3rd Year Junior High (debut)

1st Year High School

Class 1-A [1]
Style Analytic and observing player
Skills Soft touch catching

High baseball IQ Good Shoulder

First Appearance
Manga Act I - Chapter 244
Anime S2 - Episode 5
Voice Actor Yuuma Uchida
If we go up in flames, we go up in flames together. It's okay, I won't leave you to die alone.[2]
Okumura to Sawamura

Okumura Koushuu is a first year student of Seidou High. He is the roommate of Miyuki Kazuya and Kimura.


Okumura has blond hair and pale blue eyes (green in the Act I anime). He is first seen wearing a red vest, black, long-sleeved shirt, and khaki pants. 


Okumura has a quiet and very serious personality. He takes everything seriously and has a dislike for boisterous attitudes due to his middle school experience with his coach. Okumura also doesn't believe that it is possible for someone to be play baseball seriously while also being able to truly enjoy the sport at the same time. He enrolled in Seidou to see if that is possible, as well as to see how far would his abilities take him. 

Although seemingly quiet most of the time, Koushuu can be very outspoken and often very critical about matters that he pays attention to; he oftevoices his opinions on Seidou's pitchers and their respective performances and is even not afraid of a direct confrontation against Sawamura for being loud in the dining room. 




Okumura and Seto in Daikyou Senior

He was a third year junior high student and former catcher of Daikyou Senior from Kanagawa.[3][4] Okumura and Seto's baseball coach treated them nicely in the beginning, but the coach actually believed the team had no potential and suddenly left them to coach a long time rival of their school instead. Feeling betrayed, Okumura rallied his teammates to beat their former coach in a game to return him the favour.

Act I

Fall Tournament

Okumura watches Seidou's first-round match against Teito High together with his close friend, Seto Takuma, and by the end of the match, he decides to go to Seidou High School.


He and Seto watch Seidou's finals match against Yakushi High. They are shown in the bathroom talking about Raichi and his skills as both a batter and a pitcher; they soon run into fellow middle-school students Yuuki Masashi and Akamatsu Shinji and together have a brief conversation about what high school they'll be enrolling in. Seto doesn't recognize Akamatsu at first, but Okumura does.

After the match, he is seen talking to Seto and Akamatsu.

Act II

He is first seen arriving at Seidou High with Seto. They have a brief encounter with Yui Kaoru and Yuuki before heading to the dorms. He is roommates with Kimura and to his surprise, Miyuki.


Okumura and Sawamura arguing

When Miyuki hears that Okumura struggles with the amount of food, Miyuki tells him he used to be like him too when he was a first year and would actually sneak some of his rice onto Zono's plate. Okumura gets competitive and responds that then he will not leave a single rice grain on his plate ever again (although he struggles heavily with it).[5] After the intrasquad game, he doesn't make the cut to the first string, but still gets to join them at the bullpen during practice. He is seen catching for Kaneda.

One time during Seidou's dinner after most of the players have finished eating, Okumura is left with Asada and Kuki. Sawamura calls out Asada, inviting him to play catch. As Sawamura goes on talking to Asada, Okumura is annoyed by his blabbering. Okumura then bluntly states his annoyance to Sawamura, even calling him an eyesore.[6] Okumura states he really hates Sawamura's boisterous personality and that he was disappointed with him. Later, he gets lectured by Miyuki for his words, as the captain felt it could negatively affect Sawamura's performance and by extension, the team. After warning Okumura to reflect on his actions, Miyuki also suggests he should practice with Sawamura sometimes to fully understand what kind of person he is.

Although feeling irritated by Miyuki's lecture, Okumura later approaches Sawamura and offers to help him warm up after witnessing a frustrated Sawamura being left behind by Miyuki and Furuya. As he helps Sawamura warm up, he was visibly impressed with Sawamura's ability to consistently locate his pitch at the same spot. Miyuki notices Okumura's eagerness to practice more with Sawamura, so he tells them to continue. Okumura demonstrates his catching abilities for the first time, being able to react and adjust to Sawamura's breaking fastballs and catching cleanly despite this being his first experience with Sawamura's pitches. However, he could not catch Sawamura's No. 7, the Cutter Kai, which would frustrate him every time he recalled the experience.

After Seidou lost to Ichidaisan in the SF of the Spring Tournament, Kataoka announced the reset for the jersey numbers which started the competition for the summer roster. Okumura and Seto were determined to get into the first string and to do that, they would have to qualify for the second string first. He displayed more of his soft and serious side when he talked to Sawamura about how the latter could become a pitcher everyone recognized, and then stated he had to become a first-string member before he could catch for Sawamura.

In a flashback, it's revealed Okumura and Seto's middle school coach treated them nicely in the beginning, encouraging them and teaching them 'thinking baseball,' but then suddenly left them to coach a long time rival of their school. Feeling betrayed, Okumura rallied his teammates to win a game against his former coach to return him the favor. His middle school experience made Okumura despise people that were falsely nice on the surface, resulting in him disbelieving the existence of players that could be both serious while wholeheartedly enjoying baseball at the same time. It was also revealed that he enrolled at Seidou to find out whether his mentioned belief is true or not, as well as seeing how far his abilities could take him.

Okumura, along with the other first-year recruits, participated in the intrasquad game against the upperclassmen. He was subbed in for the third inning where he formed a battery with Asada. After his performance in the intrasquad game, Okumura was chosen along with three other first years to join the second string. However, despite achieving his objective of making to second string, he was dissatisfied and would decline Sawamura's offers to catch for him, stating he hasn't made it to first string yet. He wanted to fulfill his promise of making it to the first string before allowing himself to work with Sawamura; however, he would accept Furuya's request to practice in the bullpen shortly afterwards which frustrated Sawamura to no end.[7]


Seto Takuma


Okumura and Seto

Seto and Okumura attended the same middle school and played on the baseball team together. They came to Seido’s match against Teito in the Fall Tournament and after watching, decided to attend Seidou High. After enrolling at Seidou, it's obvious that Seto sincerely cares about Okumura and looks out for him, telling him that he doesn't have to push himself so hard.[8] But Okumura seems to be uncomfortable with his solicitude and made it clear that Seto didn't have to always wait for him.

Sawamura Eijun


Okumura and Sawamura

As stated by Seto, Okumura held Sawamura in high regard prior to attending Seidou, with the pitcher responding to Miyuki's aggressive game-calling by throwing pitches that exceed expectations. But shortly after his enrollment, an argument happened between the two of them when Okumura was annoyed by Sawamura pestering Asada, even saying he felt disappointed with Sawamura. He was later lectured by Miyuki for potentially affecting Sawamura's mentality and by extension, the team, as Sawamura is one of their key players. Miyuki suggested Okumura should try practicing with Sawamura to understand more about him. Taking interest in this, Okumura offered to help Sawamura warm up while the latter was waiting for Miyuki. He was impressed by Sawamura's ball control, being able to throw to the same location every time during the warm-up. Okumura seemed eager to continue practicing with Eijun which Miyuki allowed. He was visibly impressed with Eijun's Cutter Kai since he couldn't react to the pitch, missing it completely. After their catching session, it seems Okumura has opened up to Sawamura and even offers the latter his opinions on how he can become a pitcher recognized by everyone. He still seems to dislike Sawamura's shouting on the mound and suggests he should change that because it makes the pitcher looks stupid. He later makes a promise that he'll only catch for Sawamura once he gets to the first string and starts refusing Sawamura's practice offers and even direct orders from Kataoka.[9] After making the first string, Okumura comes to Sawamura and requests to practice with the latter immediately.[10]

Miyuki Kazuya


Okumura's view of Miyuki

Okumura displays what can be seen as an aggressive attitude towards Miyuki. He thinks Miyuki is fooling around when he plays because he believes it is not possible for someone to both play baseball seriously while also enjoy the game at the same time. This is completely different from Miyuki, who enjoys baseball with all his heart and plays the game out of pure love for it. However, Okumura does follow Miyuki's game-calling (which he addressed as aggressive and designed to stir up the pitchers fighting instinct) during matches with interest.


Player Statistics: Catcher


Miyuki notes Okumura possesses a soft touch when it comes to catching as he catches the pitches very cleanly, making a nice sound with his mitt. This helps ease up and instill confidence in the pitcher. It was said on multiple occasion that Okumura is a talented catcher, being able to adjust to Sawamura's difficult moving pitches and hidden form, and later Furuya's powerful and wild pitches.[11][12] Okumura also demonstrated he has strong shoulders and the solid defensive skills of a catcher, able to throw accurately right on top of a base plate for easy touch out.

Aside from his skills as a catcher, Okumura has also shown to employ a thinking-oriented play style by using an extensive process of eliminations and predictions to reduce as much risk as possible, as well as formulate a more advantageous situation for the team. He can watch pitches with precision, feint a bunt or squeeze play to trouble the pitcher, and draw balls to work the count in his favour before hitting a pitch he targets. This playing style was taught to him by his former middle school coach whom he detests, but Okumura admits that his playing style is something he cannot change or run away from at this point. Ochiai thinks that with Okumura's catching talent and his leadership qualities, if guided correctly, can make him become a catcher that represents Tokyo.[13]


  • Koushuu ranked 11th in the First Official Character Popularity Poll.[14]
  • According to Yui, most Daikyou senior players end up going to Kanagawa’s Kurebayashi or Tsuruta, yet Okumura joined Seidou.
  • He doesn't have players he admires.[15]
  • He calls Seto Takuma Taku.
  • After their quarrel,[6] Eijun gave him the nickname Wolf Brat. [16]
  • He tends to stand very close to the pitcher when he goes up for a mound visit.
  • Okumura's hitting march is Guren no Yumiya, the OP to the first season of Attack on Titan

Name Etymology

  • Okumura (奥村) - Inner Village
  • Koushuu (光舟) - Boat of Light


  • "If he was the indisputable Ace and the team's mainstay, there is no way they would have subbed him out in a situation like that; that means he hasn't earned enough trust from the coach." - about Furuya [17]
  • "And then your numbers. Once you complete them, I'm sure you'll become a pitcher everyone acknowledges." to Sawamura [18]
  • "This person, who responds to the aggressive game calling by throwing pitches that exceed every expectation, is also quite something." - about Sawamura [19]
  • "We're fighting in our own way." - to Sawamura[6]
  • "You're an eyesore, so can you do us a favour and remove yourself, senpai." - to Sawamura[6]
  • "What a bastard... Like I thought, he really is passionate deep down after all." - Sawamura
  • "You see, the thing about Koushuu is that he's always dead-serious, no matter who he's up against. That's the reason why I just can't leave him and his dangerous tendencies alone." - Seto[20]
  • "Nothing! I was just telling him [Asada] how it's never boring with you around!" - Seto[21]
  • "If we go up in flames, we go up in flames together. It's okay, I won't leave you to die alone." - to Sawamura[22]
  • "Taku... They should have given you more chances." - to Seto[23]



  1. Act II - Chapter 59
  2. S2- Episode 40
  3. Act II - Chapter 52
  4. Act II - Chapter 57
  5. Act II - Chapter 23
  6. 6.0 6.1 6.2 6.3 Act II - Chapter 25
  7. Act II - Chapter 61
  8. Act II - Chapter 21
  9. Act II - Chapter 87
  10. Act II - Chapter 97
  11. Act II - Chapter 36
  12. Act II - Chapter 61
  13. Act II - Chapter 74
  14. Act II - Chapter 51
  15. Act II - Chapter 12
  16. Act II - Chapter 32
  17. Act I - Chapter 249
  18. Act II - Chapter 51
  19. Act II - Chapter 14
  20. S2- Episode 19
  21. S2- Episode 19
  22. Act II - Chapter 127
  23. S2- Episode 42