Koki Watanabe

is a Japanese badminton player. He graduated from the Saitama Sakae High School, and was part of the BIPROGY team since 2017. Watanabe has won a Super 500 title at the Canada Open and was the runner-up in the Super 750 at the Denmark Open.

Early life and junior career Watanabe started his badminton career when he was four years old, entering the badminton club under the influence of his sister. He later concentrated on badminton in kindergarten, and when he was in elementary school, he won the Saitama school championships for three consecutive years. Watanabe entered the Saitama Sakae Junior and Senior High School, and won the singles title at the national junior championships, also placing third in the doubles event.

Career 2018–2019 In 2018, Watanabe reached his first World Tour final at the Super 100 Russian Open, finishing as the runner-up. After the international circuit resumed following the COVID-19 pandemic, he made his Super 1000 debut at the 2021 All England Open, where he lost in the first round to Viktor Axelsen. Later that year, he made his World Championships debut in Huelva, advancing to the second round. His best result of the 2022 season was a quarterfinal finish at the Australian Open.

2023 In March, Watanabe won his first World Tour Super 300 title at the Swiss Open, defeating second seed Lee Zii Jia in the semi-finals and Chou Tien-chen in the final. On the World Tour, he won his first Super 500 title at the Canada Open, defeating compatriot Kodai Naraoka in the semi-finals and Alex Lanier in the final. Later in the season, Watanabe advanced to his first Super 750 final at the Denmark Open, where he defeated Olympic silver medalist Kunlavut Vitidsarn before finishing as runner-up to Anders Antonsen.

Watanabe also reached the semi-finals of the Arctic Open and the U.S. Open, and the quarter-finals at the All England Open, China Open, and India Open. His notable victories during the season included a win over world number 3 Li Shifeng at the India Open and two wins against Olympic bronze medalist Lee Zii Jia at the China and Arctic Opens. Following these performances, Watanabe reached a career-high world ranking of 11 on 22 October.

2025 Watanabe experienced a challenging start to his 2025 season, suffering early-round exits in several tournaments, including the Super 1000 Malaysia Open and Indonesia Open. His form improved in July at the Super 750 Japan Open, where he reached the semifinals of the tournament for the first time. En route, he defeated Chou Tien-chen in the second round and Weng Hongyang in the quarter-finals. Watanabe credited advice from compatriot Kento Momota, which encouraged him to adopt a "challenger spirit" to overcome his slump. Later in the season, he reached the quarter-finals of the Arctic Open and French Open, although he was eliminated in the first round of both World Championships and China Open. In team competition, he won a bronze medal with Japanese team at the Sudirman Cup.

2026 In March, Watanabe competed at the All England Open, where he upset third seed Anders Antonsen in the opening round before being eliminated in the quarter-finals by Canada's Victor Lai. He was also a member of the Japanese squad that secured the nation's first men's team title at the Asia Team Championships. In April, Watanabe competed at the Asian Championships in Ningbo, China, defeating Zaki Ubaidillah in the first round before falling to Loh Kean Yew in the second round. In May, he reached the quarter-finals at the Thailand Open, where he defeated sixth seed Kodai Naraoka in the second round before losing to world No. 1 Shi Yuqi. Following a first-round exit at the Malaysia Masters, he advanced to the semi-finals of the Singapore Open. He defeated India's Lakshya Sen in the quarter-finals before losing to Loh Kean Yew.

Awards and nominations

Achievements World Junior Championships Boys' singles Year Venue Opponent Score Result Ref 2015 Centro de Alto Rendimiento de la Videna,Lima, Peru Lu Chia-hung 18–21, 12–21 Bronze Bronze

BWF World Tour (3 titles, 4 runners-up) The BWF World Tour, which was announced on 19 March 2017 and implemented in 2018, is a series of elite badminton tournaments sanctioned by the Badminton World Federation (BWF). The BWF World Tour is divided into levels of World Tour Finals, Super 1000, Super 750, Super 500, Super 300, and the BWF Tour Super 100.

Men's singles Year Tournament Level Opponent Score Result Ref 2018 Russian Open Super 100 Sourabh Verma 21–18, 12–21, 17–21 Runner-up 2019 Orléans Masters Super 100 Thomas Rouxel 18–21, 21–12, 21–19 Winner 2023 Swiss Open Super 300 Chou Tien-chen 22–20, 18–21, 21–12 Winner 2023 Korea Masters Super 300 Kento Momota 16–21, 15–21 Runner-up 2024 Canada Open Super 500 Alex Lanier 20–22, 21–17, 21–6 Winner 2024 Denmark Open Super 750 Anders Antonsen 15–21, 16–21 Runner-up 2026 Japan Open Super 750 Christo Popov 11–21, 19–21 Runner-up

BWF International Challenge/Series (2 titles) Men's singles Year Tournament Opponent Score Result Ref 2018 Yonex / K&D Graphics International Kodai Naraoka 21–14, 14–21, 21–15 Winner 2019 Osaka International Takuma Obayashi 19–21, 21–17, 21–7 Winner BWF International Challenge tournament

BWF Junior International (1 title, 1 runner-up) Boys' singles Year Tournament Opponent Score Result Ref 2015 Danish Junior Cup Yuta Watanabe 21–12, 18–21, 7–21 Runner-up

Boys' doubles Year Tournament Partner Opponent Score Result Ref 2015 Australian Junior International Kenya Mitsuhashi Christian Bernardo Alvin Morada 16–21, 21–17, 21–16 Winner BWF Junior International Series tournament BWF Junior Future Series tournament

Wins over top-10 ranked players Wins over players who were ranked in the world's top 10 at the time the match was played. Opponent Tournament Score 1 Lee Zii Jia 4 2023 Swiss Open SF 21–11, 21–14 37 9 Chou Tien-chen 6 2025 Japan Open 2R 16–21, 24–22, 21–17 18

Record against selected opponents Record against year-end Finals finalists, World Championships semi-finalists, and Olympic quarter-finalists. Accurate as of 23 August 2026.

Player Matches Win Lost Victor Lai 2 0 2 –2 Lin Dan 1 0 1 –1 Shi Yuqi 3 0 3 –3 Zhao Junpeng 3 0 3 –3 Chou Tien-chen 6 3 3 0 Anders Antonsen 7 2 5 –3 Viktor Axelsen 4 0 4 –4 Hans-Kristian Vittinghus 1 1 0 +1 Rajiv Ouseph 2 2 0 +2 Alex Lanier 5 2 3 –1 Christo Popov 5 1 4 –3 Kevin Cordón 1 1 0 +1 Srikanth Kidambi 2 0 2 –2

Player Matches Win Lost Parupalli Kashyap 2 2 0 +2 Prannoy H. S. 2 1 1 0 B. Sai Praneeth 1 0 1 –1 Lakshya Sen 7 3 4 –1 Kento Momota 3 1 2 –1 Kodai Naraoka 7 3 4 –1 Lee Zii Jia 4 3 1 +2 Liew Daren 3 1 2 –1 Loh Kean Yew 6 3 3 0 Heo Kwang-hee 4 2 2 0 Kunlavut Vitidsarn 7 2 5 –3 Kantaphon Wangcharoen 2 2 0 +2