"Motivation? What more do you need than pride?"
Tadashi Yamaguchi
Kanji 山口 忠
Rōmaji Yamaguchi Tadashi
Character Information
Gender Male
Date of Birth November 10
Age 16
Height 179.5 cm (5' 10.7") - April
180.0 cm (5' 10.9") - November
Weight 63.0 kg (138.9 lbs)
Background Information
Goal Practice more
Be able to play in a match as a regular
Have a greater presence
Likes Volleyball
Soft, floppy french fries
Professional Status
Occupation High School Student
(1st Year, Class 4)
Teams Karasuno High
Number 12
Position Middle Blocker
Pinch Server
Debut Information
In the Manga The King of The Court
In the Anime The Formidable Ally
Seiyu Information
Voice Actor Sōma Saitō
English Actor Cameron Bautsch

Tadashi Yamaguchi (Japanese: 山口 忠 Yamaguchi Tadashi) is a member of the Karasuno High Volleyball Club. He plays the role of pinch server in the team.


Yamaguchi is a young-looking boy with an average build. He has short black hair, often portrayed as brown or even green with a flyaway piece of hair sticking up at the top. Back in middle school, he was teased for his freckles/acne and overall scrawniness[1]. He seems to have grown into it now, and isn't bothered about it as much.

After joining the Karasuno volleyball team during games, Yamaguchi wears Karasuno's black, orange, and white uniform with the number 12 on the back. He also wears knee pads, and white volleyball shoes with black accents.

Outside of matches and practice, Yamaguchi wears a black gakuran, the Karasuno uniform.


Yamaguchi is a pretty shy person who relies on others. Though he is generally a nice person, he tends to snicker along or join in with Tsukishima whenever he's mocking others.

He is hardworking, as shown when he sought for extra training on his own and how he continued practicing outside of the team, after seeing how weak he was compared to his other teammates.

After a fatal loss in the match against Aobajōsai High, he gained a lot of confidence thanks to his teammates and Makoto Shimada, who has helped him practice the jump float serve. During the summer training camp, he even stood up against Kei Tsukishima, resulting in him being surprised at Yamaguchi's actions and even calling him "cool" for the first time. Tsukishima started working harder, and their relationship returned to normal after that event.


Original Statistics
Game Sense
Despite his skills as a server improved over time, his body control as a receiver is still lacking, resorting to body saves and unorthodox shots.
Tadashi Yamaguchi Cover

Jump Float Serve

Early in the series, Yamaguchi began practicing the jump float serve technique. Although attempting and failing the serve against Seijoh at a tight moment of the match, he worked extremely hard to improve it. Not even Nishinoya can receive his serves consistently. He made a very dangerous ace on the game against Wakutani High where the serve barely flipped over the top of the net and dropped on the opponent's zone, resulting in an ace and set point in the first set, but he was too nervous coming into the game anyway, and was scolded by an angry Keishin Ukai, but was spared after Chikara's plea. By the time Karasuno played against Aobajosai, Yamaguchi's jump float serve has managed to fool opponents since he no longer tried to serve right at the whistle. Under the tutelage of Makoto Shimada, his jump float serve can skim the top of the net to catch opponent off guard having to receive from further out before. He scored 5 points in a row while serving in the tournament.

As of mid-November:

  • Fingertip Height: 232 cm
  • Jumping Reach: 315 cm (spike) / 300 cm (block)


  • Favorite Food: Soft, floppy french fries
  • Current Concern: Whenever he thinks a cute girl has come over to talk to him, all they want to talk about is Tsukishima.
  • His star sign is Scorpio.
  • There has been debate over whether the dotting on his face is acne or freckles, but many believe that the specks are freckles.
    • In Haikyuu!! Radio #22, Yamaguchi's voice actor, Soma Saito, described Yamaguchi with the word "freckles" in a guessing game with Uchiyama Kouki, Ayumu Murase, and Kaito Ishikawa.
  • Since he's in Class 4 with Tsukishima, he must be smart; Classes 4 and 5 are college-preparatory classes in Karasuno.
  • His original reason for joining a sports club was so he could grow stronger. He chose volleyball specifically because the other sports clubs had "scary-looking guys"
  • He is the only first year to not be a regular in the first series of the anime.
  • In the fourth instance of Haikyuu!! Radio, Yamaguchi's voice actor for the anime adaption, Saitō Sōma, was asked "What sort of person is your character, Yamaguchi?" to which he responded "Loves Tsukki very much."
  • His seiyuu, Saitō Sōma, is also the seiyuu for Twelve, a character in the anime Zankyou no Terror. Number twelve is Yamaguchi's shirt number.
  • He shares a birthday with Kenji Futakuchi.
  • When asked about Yamaguchi's name origin, Furudate said, “He’s 忠 (loyalty), like a loyal dog!”[2]
    • 忠 is also how "Hachiko" is written. Hachiko is a famous loyal Japanese dog who also shares the same birthday as Yamaguchi.
  • Nomenclature:
    • Tadashi (忠) - Loyalty; Devotion
    • Yamaguchi (山口) - Mountain Entrance


  1. Chapter 87
  2. Haikyū!! Guidebook