Prince of Tennis Wiki
Sadaharu Inui



Inui Sadaharu








184 cm


62 kg


June 3



Blood Type




Junior High

Seigaku (3rd Year)



Club Position


Elementary School

Midorigawa First (Dai-ichi) Elementary School

Japan U-17 Camp

Court 2

Dominant Arm


Play Style

Serve and Volley

Doubles Partner(s)

Yanagi Renji
Kaidō Kaoru
Momoshiro Takeshi (Anime Only)


Prince (Graphite Challenge)


Puma (Sequence PT0636 0067)

Manga Debut

Genius 4

Anime Debut

Episode 3


Atobe's Gift
The Prince of Tennis - The Two Samurai: The First Game
Battle of the British Castle

Voice Actor

Kenjiro Tsuda (Japanese)
Jack Bauer (English)

Sadaharu Inui (乾貞治 Inui Sadaharu) is a 3rd-year student and regular member of the Seigaku tennis team. He is an intelligent player and is best known for collecting player data, which he incorporates into a unique playing style known as "Data Tennis". During his match against Tezuka in the manga, it is hinted that he is the 3rd strongest 3rd year in Seigaku, behind Tezuka and Fuji.


Yanagi and Inui after practice at age 10.

Four years prior to the start of the series, Inui and Yanagi Renji were an unstoppable Elementary School Doubles Pairing. Despite Inui wanting to continue their close partnership, their doubles pairing was ended when Yanagi suddenly moved to the Kanagawa Prefecture and joined Rikkai Daigaku Fuzoku.

Before Echizen Ryoma's arrival at Seigaku, Inui was recognised as the third-strongest player on the team, next to Fuji Shūsuke and Tezuka Kunimitsu. Inui has an intense rivalry with Tezuka, having played at least 30 matches against him and losing every single one of them. In response to Tezuka's superiority, Inui began developing his style of Data Tennis specifically to defeat Tezuka. Despite being in the regular lineup for six months, Inui was beaten by Ryoma in the intra-school ranking tournament, and then lost to Kaidō Kaoru (who had also been beaten by Echizen and was determined not to lose his spot) at the beginning of the series. Late on, he became the team's manager. He uses his data to create exercise programs for the team.

Eventually, Inui is able to make it back as a regular by using the data he obtained over the time he was manager, defeating Momoshiro Takeshi, thus regaining his spot in the regulars. Despite his guaranteed spot, he played a tough match against the undefeated Tezuka and again lost to his captain. Nonetheless, Inui is enthusiastic about regaining his spot on the team. He is eager to practice with his teammates and resume his data-gathering.

While he is a very good singles player, Inui usually plays doubles with various partners, most notably his protegé Kaidō Kaoru. His doubling with Kaidō helped Seigaku overcome their problems with their lack of strong doubles teams, with the exception of the Golden Pair.


Inui has fairly short, spiky black hair. He is very tall and wears thick black framed glasses. They are so thick to the point where people are unable to see his eyes. Inui's eyes have only been shown a few times through out the manga but they are brown like most other characters. This is also due to the fact that no one has ever seen him taking off his glasses, not even Tezuka.

In anime his eyes are shown to be green in color. He typically wears shorts and a t-shirt when not wearing his regulars jacket, like the other members of the team.


Inui is quite intelligent, proven by his playing style. He is also hardworking, proven by his quick improvement during the timespan between the Prefectuals and the Kantō arcs. Due to his falling out as a regular, he took on a training regimen which was 2.25 times harder than Kaidō's, whose training regimen was already 3 times harder than his fellow teammates.

However, he does have his quirks, just like the rest of the team. One of Inui's most notable traits is his penchant to brew horrible vegetable juices (named "Inui Juices"), which he uses mostly in practice as punishment for players who fail the training menus. Only he and Fuji dare to drink. He. however, do not understand why people are so afraid of them since he finds them to be very beneficial for the body and delicious (most times).

Inui carries several of the same glasses when playing.

Inui often spies on his teammates outside of school or practice, such as the time when Tachibana Ann took Momoshiro on a tennis date, or when Kawamura went on a "date" with Akutsu Jin's mother Yūki, whom everyone mistook for his girlfriend since she was a beautiful and very young-looking woman. He also spies on people from other teams, like when he went to report on the Ginka team right after Ryoma Echizen defeated them to rescue Ryuzaki Sakuno from their bullying. He even does this in the last episode of the manga, where he spies on Fuji teasing Tezuka. Due to this Inui is very observant and can often pick out small vital pieces of information that a majority of his team can not.

He is usually seen carrying a notebook around, in which he scribbles all the data he has gathered -- including personal data. He believes that "data does not lie" and relies on it very heavily when playing tennis. He would often use data outside of tennis, for example often putting a percentage on whether an action would fail or succeed.



Due to Inui being dropped out of the Regulars, he is unable to participate in the Tokyo District tournament. However, he proves himself to be very competent by not only devising various training regimen for his team, but he also collects various data on his school's opponents, being the first to find out that the Fudomine team had completely changed compared to the previous year.

Tokyo Prefecturals

Inui and Seigaku entered the Prefecturals as amongst the favorites.


Regional Select Invitationals Camp

Inui and the Seigaku regulars recieve invitations to the Regional Invitationals Camp

Regional Select Invitationals

Inui sits in the audience during the match between Kanto Region Japan Junior Representatives against the USA West Coast Region Junior Representatives.


In last finals he plays doubles with Kaido against Rikkai's Yanagi and Kirihara but lost at the end.

Prior To U-17 Camp

U-17 Camp

Inui in his Black U-17 Camp Uniform.

After winning the Nationals with Seishun Gakuen, Inui and the other 8 regulars of Seigaku are invited to Japan's U-17 training camp. During one of the training programs at the camp, all the middle schoolers are told to pair up; due to his usual partner Kaidō partnering up with Tezuka and his childhood friend Renji pairing up with his underclassman Kirihara Akaya, Inui is left with a fellow Data Tennis player Mizuki Hajime, believing that they'll be having a doubles match. However, the coach in charge of the program, Mental Coach Saitō Itaru, suddenly announces that all the pairs must play a tie-breaker Singles Match against each other where the loser must leave the camp. Due to a miscalculation in an ingredient in one of his Inui Juices, however, Inui ends up with a minor case of diarrhea/some form of stomachache and is unable to make it to his match in time, thus being forced to forfeit his match.

Fortunately, however, Inui and everyone else that lost their tie-breaker match gain a chance to redeem themselves by training up in the mountains with the Drunken Coach and all the other middle schoolers that lost their tie-break games. Afterwards, all 25 middle schoolers that lost their tie-breaks arrive back to the U-17 camp and defeat the 8 original members of the 2nd Court, allowing Inui and the rest of the members that lost their tie-breaker match to be the current member of the 2nd Court.

U-17 Camp Revolution

Renji & Inui meets Mitsuya Akuto

When Renji challenges Mitsuya Akuto, Inui accompanies them, watching from the sidelines. Partway through the match, Renji loses motivation to continue because he calculates that the probability of his victory was 0%. Inui, however, calls out to him and reminds him of the nationals, convincing Renji to discard his data and play with all he has. Renji loses the match and collapses, entrusting the match to Inui, who had a 33.1% probability of winning, likely due to the data he was able to collect during Renji's match.

It appears that Inui defeated Mitsuya Akuto, but Renji is seen wearing the No. 17 badge instead of Inui when the middle schoolers return to the courts.

Tennis Record

See: Tennis Record

Playing Style and Techniques

See: Playing Styles & Techniques

Inui Juice

Inui created several Inui Juices as punishment for his teammate's failures.

Personal Information

  • Family Composition: Father, Mother
  • Father's Occupation (Family Business): Public Officer
  • Spends Allowance On: Note Book and Literature Reference Book
  • Motto: Knowledge is an Everlasting Treasure
  • Best Subjects: Physics
  • Worst Subjects: Home Economics (esp. Cooking)
  • Committee: School Festival Planning Committee
  • Places often visited in school: Third Archive Room
  • Favourite Colour: Black
  • Favourite Food: Durian (Momoshiro's guessing), Soup Spaghetti (Eiji’s guessing)
  • Favourite Movie: Korean Movie
  • Favourite Book: Mystery Novels
  • Favourite Music: Any Type
  • Favourite Type: Calm and collected person, preferably older woman
  • Place you want to go for dates: Art Museum
  • Thing you want most now: Latest Design Mixer
  • Routine duties: Organizing Data and Glasses Care and Cleaning
  • Dislikes(/bad at): Lightning Strike, Electricity Failure (Because he can’t use the computer)
  • Skills outside of tennis: Othello, Shougi, Chess, Go
  • His first love lasted a total of 4.2 seconds

Bag Check

  • Laptop + calculator
    A laptop for storing data, and a calculator for calculating trajectory and probabilities.
  • Recording/playback MD player
    Something to verbally note down things he just thought of or to record when he hears information from someone.
  • 8mm video tape
    Clips he has taken are contained inside this handy video [tape]. They are mostly matches of Seigaku and other schools.
  • Secret notebook + rule book
    In the secret notebook, is the data of a certain great player. The rule book is used to guide kouhais.
  • Hole-puncher
    Used when he files sheets of paper that he has written data on. Not to mention that he uses two hole[-punchers].
  • Digital camera
    Used to record form checks of Seigaku members, and the situation on tournament grounds.
  • Counter + [tape] measure
    These derive all kinds of numerical data. Used together with the calculator or the laptop.
  • Binoculars
    To be able to see the details no matter how far a match is, this is a high-magnification binoculars. A 10,000 yen product.


  • “It’s a good course, but it won’t work!” (“Ii course dake do, hazure da!”)
  • “As long as I can anticipate your shots, no matter how good your shot is, there won’t be a ball I can’t return.” (“Kaete kuruba shosai wakare ba, donna ni ii shot demo, uchi kaesenai tama wa nai yo.”)
  • “This is illogical.” (“Rikutsu ja nai.”)
  • “Tezuka, I’ve collected the data. I’ll make you lose this time.” (“Tezuka, data wa atsuma ta. Konkai wa katasete morau yo.”)
  • “I just wanted to climb up a little bit to the top.” (“Chotto ue ni nobotte mitaku na tene.”)
  • “Tezuka, data won’t lie.” (“Tezuka, data wa uso wo tsukanai yo.”)
  • "Kaido, would you like to play Doubles with me?" (“Kaido, ore to doubles kun de miru ka?”)
  • "Even though I thought I would be cautious for the first half of the game, I will go on the offensive too." ("Zehan wa shinchou ni ko ka domo te ita ga, ore mo seme sasete morau yo.")
  • "Probability of a straight: hundred percent." ("Straight no kakuritsu: hyaku percent.")
  • “Just as I expected.” (“Kesan dori da.”)
  • "Nuooooah!"
  • (To Renji) "If my data tennis is being read completely then...I will throw away all my data."

Running Jokes in the Anime

  • Inui attempting to escape a punishment he cannot take, and the result is usually something worse, such as:
    • Ex: His avoidance of the "Silver Seat", by taking a hit to the face with a volleyball resulted in his partner, Kisarazu Ryō, accidentally pulling off his swim trunks
    • Ex: Inui slipping on the dinner table at Nikubiku Garden during the Yakinuki Battle, and adverently gets his pants pulled down and his privates burned by the grill due to Tezuka's attempts to save him.
  • Inui habitually appears behind others unannounced
  • Inui using his data and math formulas to win games such as Bowling and Billiards, but only to fail.
  • Other characters attempting to see Inui's face without his glasses
  • Various situations involving Inui Juice, mostly using it as punishment.
  • One night during the training camp prior to the match against Rikkai, Ryoma attempts to catch Inui without his glasses. However, he is thwarted when Inui turns and shows that he is wearing a blindfold.


Inui's eyes in Atobe's Gift

Inui's eye from episode 168

  • In the anime, both of Inui's eyes are first seen in the short movie Atobe kara no Okurimono (Atobe's Gift in English). When Inui is jumping during one of the competitions held by Atobe in the festival, both of his eyes are revealed. Prior to that, only one of his eyes were shown in the anime series; during episode 168, which Inui's glasses were broken in a regulars match with Kikumaru Eiji. In the manga, we can see his eyes during the match against Yanagi Renji (Chapter 211 pgs 18-19), and we can see another picture of his eyes in the cover of his single "Distance".
  • In the TeniPuri Family chibi episodes Inui is the father of the family and can always be seen quoting data and statistics. He's also often beaten up by Oishi, who plays the mother of the family and has a rather volatile temper.