is a Japanese badminton player who competes in singles. He plays for the AC Nagano Parceiro Badminton Club, having previously played for NTT East. His junior international achievements include a gold medal in mixed doubles at the 2013 Asian Youth Games and bronze medals with the national team at the 2014 Asian and World Junior Championships. While studying at Waseda University, he won the men's singles title at the All Japan Intercollegiate Championships in 2017 and 2018. On the BWF World Tour, his best result was a runner-up finish at the 2018 Canada Open.
Koga was born on 30 September 1996, in Fukuoka, Japan. He began playing badminton at the age of six at the Okagaki Junior club. In 2011, while a second-year student at Tomioka Daiichi Junior High School in Fukushima Prefecture, he evacuated the area following the Great East Japan Earthquake.
At the national level, Koga won the junior singles title across all three major age divisions: the All Japan Elementary School Championships (2008), the All Japan Junior High School Championships (2011), and the (2014). At the 2014 Inter-High, he defeated Kanta Tsuneyama in the singles final and led Tomioka High School to the team title. On the international junior stage, Koga won a gold medal in mixed doubles at the 2013 Asian Youth Games, partnered with Akane Yamaguchi. He also contributed to the Japanese team winning bronze medals at both the 2014 Asian and World Junior Championships.
Koga enrolled at Waseda University in 2015, majoring in sport sciences. He won the men's singles title at the in two consecutive years (2017, 2018). In his final year, he captained the Waseda team to a national intercollegiate team title.
While a student at Waseda University, Koga reached the final of the 2018 Canada Open (Super 100). Despite entering the tournament ranked world No. 396, he reached the final before losing to Lu Guangzu.
Following his graduation, Koga joined the NTT East badminton team on 1 April 2019. He was selected for the Japanese national B team (2018âÂÂ2022) and was part of the squad that won silver at the 2019 Asia Mixed Team Championships.
Koga won his first senior international title at the 2019 Swedish Open, defeating future world champion Loh Kean Yew in the final. Later that year, he reached the semifinals of the 2019 Vietnam Open, a run that included a victory over another future world champion, Kunlavut Vitidsarn.
Between 2022 and 2024, Koga won five additional international titles: the 2022 Mexican International, three titles in 2023 (Thailand, Malaysia, and Bahrain), the 2024 Malaysia International. He achieved a career-high world ranking of 56 on 21 March 2023.
Domestically, Koga became a two-time champion of both the All Japan Members Badminton Championships (2019, 2023) and the Japan Ranking Circuit (2021, 2023).
On 1 April 2025, Koga transferred to the AC Nagano Parceiro badminton club. That year, he won two titles at the Slovenia Future Series and the Belgian International, and finished as runner-up at the Lagos International.
Koga began the 2026 season with strong performances on the European circuit. In January, he secured consecutive titles by winning the Estonian International and the Swedish Open. In both finals, he defeated DenmarkâÂÂs Mads Christophersen.
At the German Open (Super 300), Koga advanced through the qualifying rounds to reach the main draw. In the first round, he recorded an upset by defeating the second seed and world No. 6, Li Shifeng, in straight games.
His elder brother, Akira Koga, is also a badminton player affiliated with JTEKT Stingers.
Mixed doubles
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 Tours are divided into levels of World Tour Finals, Super 1000, Super 750, Super 500, Super 300 (part of the HSBC World Tour), and the BWF Tour Super 100.
Men's singles
Men's singles
Record against Year-end Finals finalists, World Championships semi-finalists, and Olympic quarter-finalists. Accurate as of 15 March 2026.