is a Japanese badminton player who competes in men's doubles. A left-handed player, he is a member of the Japanese national team and represents the BIPROGY badminton team. Partnering with Hiroki Nishi, he reached a career-high world ranking of No. 19. Kumagai won his first BWF World Tour title at the 2025 Kaohsiung Masters (Super 100), and was a member of the Japanese squad that won the country's first men's team gold medal at the 2026 Asia Team Championships. A graduate of sport science at Nihon University, Kumagai won the men's doubles title at the 2023 All Japan Inter-Collegiate Championships.

Early career Junior career Kumagai began playing badminton at the Sendai Yamato Junior club before attending Saint Ursula Gakuin Eichi Junior and Senior High School. In 2018, he partnered with Yoshifumi Fujisawa to win the boys' doubles title at the All Japan Junior Championships.

The following year, Kumagai represented Japan at the 2019 World Junior Championships, winning a bronze medal in the mixed team event. In the individual mixed doubles event, he and partner Mizuki Otake reached the quarterfinals, where they were defeated by the Chinese pair Jiang Zhenbang and Li Yijing in three games match (20–22, 21–18, 21–23).

University career Kumagai studied sport science at Nihon University. Partnering with Kota Ogawa, he won the men's doubles title at the 2023 All Japan Student Championships (Inter-Collegiate). Consequently selected for the Japanese national B team, the pair made their World Tour debut at the 2023 Indonesia Masters I Super 100, finishing as runners-up.

Career 2024 After graduating from university in April, Kumagai joined the BIPROGY badminton team. He formed a men's doubles partnership with Hiroki Nishi, training under former national players Hiroyuki Endo and Kenichi Hayakawa. In their debut season, the pair finished as runners-up at the Super 100 Odisha Masters and the Kazakhstan International. Domestically, at the All Japan Corporate Team Championships, Kumagai partnered with Yuta Watanabe to defeat the former world No. 1 pair, Takuro Hoki and Yugo Kobayashi, in the final. This victory secured the team title and earned the pair the Men's MVP award.

2025 Kumagai and Nishi claimed their first international title as a pair at the Northern Marianas Open in August, defeating compatriots Haruki Kawabe and Kenta Matsukawa in the final. They subsequently won their first World Tour title at the Super 100 Kaohsiung Masters. The pair also finished as runners-up at the Super 100 Indonesia Masters I and reached the quarterfinals of two Super 500 tournaments: the Japan Masters and the Australian Open. Following these results, they reached a career-high world ranking of No. 32 in November.

2026 Kumagai and Nishi opened the season by making their Super 1000 debut at the Malaysia Open. The pair advanced to the second round, where they were defeated by their compatriots Takuro Hoki and Yugo Kobayashi. He was part of the Japanese team that won Japan's first men's team title at the Asia Team Championships. In the final against China, Kumagai and Nishi defeated He Jiting and Ren Xiangyu in three games to help secure the victory. In April, Kumagai made his Asian Championships debut in Ningbo, China, partnering with Nishi in men's doubles. They defeated Peeratchai Sukphun and Pakkapon Teeraratsakul in the first round before being eliminated in the second round by Liang Weikeng and Wang Chang. In May, Kumagai competed in his first Thomas Cup in Horsens, where the team finished in fifth place. He achieved a career-high world ranking of 19 on 6 October.

Achievements BWF World Tour (1 title, 3 runners-up) The BWF World Tour, which was introduced on 19 March 2017 and was held in 2018, is a series of elite badminton tournaments sanctioned by the Badminton World Federation (BWF). The BWF World Tours are divided into levels of World Tour Finals, Super 1000, Super 750, Super 500, Super 300, and the BWF Tour Super 100.

Men's doubles Year Tournament Level Partner Opponent Score Result Ref 2023 (I) Indonesia Masters Super 100 Kota Ogawa Sabar Karyaman Gutama Muhammad Reza Pahlevi Isfahani 18–21, 15–21 Runner-up 2024 Odisha Masters Super 100 Hiroki Nishi Huang Di Liu Yang 13–21, 21–19, 25–27 Runner-up 2025 (I) Indonesia Masters Super 100 Hiroki Nishi Jin Yong Na Sung-seung 19–21, 21–13, 13–21 Runner-up 2025 Kaohsiung Masters Super 100 Hiroki Nishi Su Ching-heng Wu Guan-xun 21–18, 21–17 Winner

BWF International Challenge/Series (1 title, 1 runner-up) Men's doubles Year Tournament Partner Opponent Score Result Ref 2024 Kazakhstan International Hiroki Nishi Lucas Corvée Ronan Labar 14–21, 19–21 Runner-up 2025 Northern Marianas Open Hiroki Nishi Haruki Kawabe Kenta Matsukawa 21–15, 23–25, 21–13 Winner

BWF International Challenge tournament

Performance timeline

National team Junior level Team events 2019 World Junior Championships B

Senior level Team events 2023 2024 2025 2026 Asia Team Championships NH A NH G Asian Games A NH 5th Thomas Cup NH A NH 5th World University Games QF NH A NH

Individual competitions Junior level Boys' doubles Events 2019 World Junior Championships 2R

Mixed doubles Events 2019 World Junior Championships QF

Senior level Men's doubles Events 2023 2024 2025 2026 Asian Championships A 2R Asian Games A NH QF World Championships DNQ NH DNQ 2R World University Games 3R NH A NH

TournamentBWF World Tour Best 2023 2024 2025 2026 Malaysia Open A 2R 2R ('26) All England Open A 1R 1R ('26) Swiss Open A 2R 2R ('26) Ruichang China MastersA 2R A 2R ('25) Orléans Masters A QF QF ('26) Thailand Open A 1R A 1R ('25) Malaysia Masters A QF QF ('26) Singapore Open A 1R 1R ('26) Indonesia Open A 1R 1R ('26) Australian OpenA QF A QF ('25) Macau Open NH A 2R A 2R ('25) Japan Open A 2R 2R ('26) China Open A QF QF ('26) Taipei Open A 1R A 1R ('25) Korea Masters 1R A 1R A 1R ('23, '25) China Masters A 1R 1R ('26) Indonesia Masters Super 100 F A F A F ('23, '25) 2R QF Arctic Open A 1R 1R ('26) Denmark Open A Q ('26) Malaysia Super 100A SF A SF ('25) French Open A Q ('26) Korea Open A Q ('26) Japan Masters 1R A QF Q QF ('25) Kaohsiung Masters 1R A W A W ('25) Guwahati Masters A QF A QF ('24)Odisha Masters A F A F ('24) Year-end ranking 82 108 34 34 Tournament 2023 2024 2025 2026 Best

Record against selected opponents Record against year-end Finals finalists, World Championships semi-finalists, and Olympic quarter-finalists. Accurate as of 27 September 2026.

Hiroki Nishi

Players Liang Weikeng & Wang Chang 1 0 1 –1 Lee Jhe-huei & Yang Po-hsuan 1 1 0 +1 Satwiksairaj Rankireddy & Chirag Shetty 1 0 1 –1 Takuro Hoki & Yugo Kobayashi 1 0 1 –1 Goh Sze Fei & Nur Izzuddin 2 0 2 –2 Kim Won-ho & Seo Seung-jae 3 0 3 –3

References

External links

Kakeru Kumagai at Badminton Association of Japan

Kakeru Kumagai at BIPROGY Kakeru Kumagai at J Sports Kakeru Kumagai at Mizuno