Koki Kumasaka

University football

Enrolled at the Tokyo International University, he helped his side to second place in the Kanto University Division 1 League. With four goals and two assists, he was named in the best XI for the league.

Kashiwa Reysol

Having already played for them for six years during his youth, Kumasaka committed to re-join J1 League club Kashiwa Reysol in July 2023. He made his professional debut in Reysol's 1–1 J1 League draw against Albirex Niigata on 30 March 2024, and went on to appear in the next three matches. An injury during the Chibagin Cup limited his playing time, and his debut season was not seen as successful. After ten league appearances in 2024, Kumasaka remained in the first team the following season, featuring in Reysol's pre-season preparation before playing ninety minutes in their opening J1 League fixture against Avispa Fukuoka. Following the appointment of Spanish manager Ricardo Rodríguez in February 2025, Kumasaka began to feature a lot more in the Kashiwa Reysol first team, forming a partnership with Riki Harakawa. In March of the same year, he changed his contract type from Pro C to Pro A, having played 450 minutes in the J1 League.

Without having previously represented Japan at youth international level, he was called up to the senior squad in May 2025.

Kumasaka primarily plays as a defensive midfielder or deep-lying central midfielder.Standing at 1.85 m, he combines physical strength and a long reach with mobility and technical ability. He is particularly noted for his ball-winning ability, his one-on-one defending and his capacity to cover a large area of the pitch. Japanese football media have described him as a physically imposing defensive midfielder whose long reach helps him intercept passes and win challenges. His game is not limited to defensive work. Kumasaka is also involved in the build-up phase, where he often positions himself in front of the centre-backs to receive the ball and initiate attacks. He has been noted for his ability to turn under pressure, play progressive passes and decide whether to play forward or recycle possession depending on the situation. His positioning and distribution have been described as an important part of Kashiwa Reysol's build-up play. Kumasaka also possesses a high work rate and is capable of contributing across a wide area of the midfield. He has described his own style as dynamic, while his ability to combine physical defending with possession play developed during his university career, following his earlier development in Kashiwa Reysol's academy. His combination of size, defensive ability, mobility and build-up play has attracted attention as a relatively uncommon profile among Japanese midfielders.

Club

As of 23 May 2025.

Notes