Diamond no Ace Wiki
Tanba Kōichirō
Seidou High School - No. 1
Bats: Right Throws: Right
Kanji 丹波 光一郎
Gender Male
Age 18 (debut)


Date of birth 10 April
Place of birth Tokyo
Bloodtype A
Height 185 cm (6' 1")
Weight 77 kg (169 lbs)
Education 3rd Year High School (debut)

Seidou Alumnus [2]

Class 3-C (former)
Skills 140 km/h Fastball


First Appearance
Manga Act I - Chapter 8
Anime S1 - Episode 4
Voice Actor Masakazu Morita
You are the ace from here on. Pitch with that in mind.
Tanba to Sawamura in Decision

Tanba Kouichiro was the ace pitcher of the Seidou High School baseball club. He applied for one tryout and despite not having high hopes of passing, he passed the tryout.


In his first year he was really shy and it took him three years to understand how a real ace must be. Because of injuries, he had withdrawn from the front lines again and again. For that reason he’s thirsting for a chance to pitch and has a strong attachment to the mound. Finally in his last year of high school, he gains the trust of the coach and the whole team and becomes the ace. But being the starting pitcher and the ace of a school which is famous for baseball often brings him a lot of stress.

He’s too serious and quiet, people tend to think he is blunt but in reality he’s extremely considerate to friends. He has a passionate side to him when he gave a roar of triumph on the mound after getting the batter out at the critical moment.

Relationship with other Characters[]

Sawamura Eijun and Furuya Satoru[]

Sawamura and Furuya are the freshmen who had threatened Tanba for the ace position, and fired him up to enhance his pitching and develop his forkball. As the ace, he realized his role to inspire and challenge his fellow pitchers without letting them overshadow him.

Miyuki Kazuya[]

He resents Miyuki's straightforward conversation with him regarding his pitching skills. However, knowing Tanba had to work with him on important games, he has no choice but to work with him and respond to his calls. They do well as battery despite their difference and both respect each others abilities as they pair up longer.

Takigawa Chris Yuu[]

Chris is the catcher who Tanba wants to form a battery with before they graduate. However, he never had a chance to pitch for him because as soon as he earned his place, Chris was forced to retire due to an injury. Chris noticed an injury that could have affected the course of Tanba's high school career. He was able to successfully recover from it and resume pitching as the teams ace.  Tanba  has great respect for Chris and expresses his appreciation for his action and concerns. His greatest wish for Chris is his full recovery from his shoulder injury and his return to the first-string team for their final year.

Manaka Kaname[]

Tanba and Manaka are good friends who grew up playing baseball together and both played the pitcher position. In Junior High, Tanba tells Manaka that he'll be going to Seidou High wanting to change himself, and not to continually walk in Manaka's shadow. When they graduate from middle school, they promise each other to become aces of their teams and fight it out at Koshien.


You're a much better pitcher than you give yourself credit for.

Tanba hurt his arm in autumn of his second year in high school, and returned to the team in Spring of his third year. After his return, he learned how to throw a powerful curveball which is his best weapon.

Pitcher’s Data[]


Player Statistics[]

Physical Strength
Mental Strength


  • Favorite food: Seafood [3]
  • Best Subject: Modern National Language[3]
  • Hobby: Reading (Personal development books)[3]
  • Favorite books: Okamoto Tarou "Tarou ni Kike!" series [3]
  • He has respect for Kuwata Masumi.[3]
  • Rankings from the guidebook:[3]
    • The break of his breaking balls ranks third.
    • He ranks fifth at Fielding.
    • The speed of his pitches ranks fifth.
  • Seidou Baseball Club secret rankings:
    • Tanba has the third cleanest room.
    • When it comes to skillful singing, Tanba ranks first. His best performance is the song "Yell” by Kobukuro.
  • Being the starting pitcher for a school famous for its baseball club often brings him a lot of stress. [4]
  • He wants to repay the coach for recommending he play a match in his 1st-Year. [4]
  • In the Fall of his 2nd-year, he injured his arm and only returned the club/team at the start of his 3rd-Year. [4]


  • "Even though he is blessed with a good physique, he is delicate. I wonder if there were a lot of people where were worried (laughes)" - Kominato Ryousuke [3]



  1. Act II - Chapter 23
  2. Act I - Chapter 412
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Official Guide Book - Omote
  4. 4.0 4.1 4.2 Act I - Volume 10: Character Profiles