Haikyū!! Wiki
Haikyū!! Wiki

Kōji Sekimukai (Japanese: 関向 (せきむかい) 幸治 (こうじ) Sekimukai Kōji) is Hinata's former classmate from Yukigaoka Junior High. He was originally on the boys' soccer team but played on the volleyball team so Hinata could have enough members to go to the competition.

As of 2018, he is a college senior.


He has spiky, dark brown hair, long eyebrows of the same color, and a medium build.

Post-timeskip, he appears mostly unchanged but his hair is now at a shorter length.


Kōji appears to be tough and brash, but blushes and gets embarrassed when Hinata compliments him. He cares a lot about his friend, going as far as to attend Karasuno's match against Shiratorizawa to support Hinata as well as his debut game in the V-League.


Kōji reassures Hinata that their team would win.

Kōji attended Yukigaoka Junior High with Hinata and Izumi before graduating to an unknown high school. In his third-year, he and Izumi joined the boys' volleyball club as temporary members so the team could attend the Junior High Athletics Meet. However, they were shocked when their first opponent turned out to be the champion school Kitagawa Daiichi. As expected, Yukigaoka was completely annihilated by Kitagawa Daiichi Junior High[1].


Kōji is first introduced in the series when he takes part in the middle school volleyball tournament that Hinata wanted to participate in. Despite being a soccer player, Kōji agreed to be on Hinata's team so he could have enough players to form a team and play. Though initially nervous at having to face off against the taller and more intimidating players of Kitagawa Daiichi Junior High, Kōji still tries to play to the best of his abilities. Because Kōji is not familiar with the rules and plays of volleyball, he has to rely on Hinata throughout the game. At times, Kōji can be seen trying to use his soccer skills to save a ball. After the match, Kōji and Izumi try to comfort Hinata and Hinata in turn thanks them once more for agreeing to join his team; causing Kōji to cry but attempt to pretend he isn't.

Soon after, the three graduated from middle school. Kōji and Izumi went on to an unknown high school together while Hinata attended Karasuno High.

Spring High Preliminary Arc

Izumi and Kōji greet Hinata.

Kōji and Izumi go to watch Karasuno play against Shiratorizawa[2]. When Karasuno arrives at the gym, the two call out to Hinata, who's surprised and thrilled about their presence. As Hinata introduces them to Tanaka, the two sheepishly admit the sports teams they were on originally and Tanaka excitedly points out Kōji's adept footwork. Suddenly, Kōji notices Kageyama and angrily asks Hinata why he's there. Jokingly, Hinata explains the changes Kageyama had gone through before the latter calls him away. After Hinata leaves, Kōji and Izumi admit to each other how when they text, they never ask Hinata about how he's been and weren't expecting to see him now with a complete team.

Soon, the two go inside the stadium to cheer on Karasuno and are overwhelmed to see Shiratorizawa's large cheering squad. They look at the other Karasuno members, only to see them stressing over the match while making fools of themselves. Disappointed, Izumi comments on Karasuno's appearance, much to Shimada and Takinoue's embarrassment.

As the match begins, the two worry about Hinata and wonder if he has to go to the bathroom one more time. Karasuno does badly right away and Kōji cheers on the team. Throughout the match, he comments on Hinata's performance while supporting Karasuno loudly. The two join in when Saeko starts a cheer for the team[3].

After the match ends in Karasuno's victory, the two go outside to congratulate Hinata and Kageyama before Ushijima interrupts them. After he promises to defeat Hinata the next time they face each other, a shocked Kōji wonders about Hinata's influence with other volleyball players[4].

Tokyo Nationals Arc

Kōji is with Izumi as they watch Karasuno play against Kamomedai. They both show great concern when Hinata collapsed from his fever[5].

Final Arc

Kōji and Izumi come to support Hinata in his debut game with the MSBY Black Jackals against the Schweiden Adlers. At the time of the match, Kōji is a college senior[6].


Since Kōji was originally on the soccer team, his volleyball skills are very poor. However, he has incredible footwork that allowed him to move around quickly on the court and occasionally make a save with his feet.


Shōyō Hinata

Hinata Koji Izumi s1-e1-1.png

They are close friends and attended the same junior high. Though he teases Hinata often, Kōji is deeply protective of him and would lash out at anyone who insulted him, Kageyama for example. He reassured Hinata during the junior high tournament and in return, Hinata encouraged Kōji during the match whenever he messed up. Even after graduating from junior high, they keep in touch through text, though Hinata never spoke about his new team. Kōji and Izumi would later attend the finals game between Karasuno and Shiratorizawa to support Hinata and were also present for Hinata's debut game in the V-League.

Yukitaka Izumi

Koji and Izumi s3-e1-2.png

They are close friends and attended the same junior high. In their third-year, they supported Hinata by joining his team together and helped each other with volleyball terms during the match. Even after graduating from junior high, they kept in touch through text and even planned together to attend Karasuno's match against Shiratorizawa and Hinata's debut game after joining the MSBY Black Jackals.