Akane Yamaguchi

In 2012, Yamaguchi began her junior international career. At the Asian Junior Championships, she won a bronze medal in girls' singles and was part of the Japanese team that won the nation's first mixed team title. Later that year, she claimed a silver medal in girls' singles and the mixed team event at the World Junior Championships. Yamaguchi also made her senior international debut that year at the Osaka International.

In April 2013, Yamaguchi finished second to Kaori Imabeppu at the Osaka International in the women's singles event with a score of 20–22, 16–21. She was the women's singles runner-up in the New Zealand Open, a Grand Prix tournament. She participated in the Japan Open, unseeded. She defeated P. V. Sindhu, the bronze medalist from the 2013 world championships in two straight games in round sixteen. She also defeated seeded player Tai Tzu-ying in a semi-final, leading to her match-up with her compatriot Shizuka Uchida, whom she beat in the final to become the youngest player to win the BWF Superseries tournament, aged only 16. This was also Japan's first ever victory at the home event since 1981.

One year after losing the final at the world juniors competition, Yamaguchi won the title by beating her teammate Aya Ohori. While in high school, Yamaguchi won the national badminton competition, competing in the women's singles event. At the 2nd Asian Youth Games held in Nanjing, China in August 2013, where she represented Fukushima Prefectural Tomioka High School, she won the gold medal in mixed doubles. In October, she represented Japan at the East Asian Games held in Tianjin, China, where she finished third in the women's singles event, losing in three sets to Wang Shixian. After graduating from high school, she joined the Saishunkan Pharmaceutical badminton team.

Yamaguchi was named the Most Promising Player of the Year by the Badminton World Federation in late 2013 and 2014.

At the Malaysian Open in January, Yamaguchi defeated reigning world champion Ratchanok Intanon in the first round in three games. In February, still a teenager, Yamaguchi entered the 2014 Asian Junior Championships as the fourth seed. She won the title by defeating Chen Yufei from China. She competed at the All England Open in March. She defended her World Junior crown, winning against Chinese player He Bingjiao in the final round.

She was part of the Japanese team that won the silver medal at the 2014 Uber Cup. On 16 August, Yamaguchi served as the flag-bearer for the Japanese team at the opening ceremony of the 2014 Summer Youth Olympics in Nanjing, China. She was the number one seed in the women's singles event, eventually winning the silver medal.

At the China Open in November, Yamaguchi defeated top ranked players in two straight games, Wang Shixian, Sun Yu, Bae Yeon-ju and reached the final. She finished as runner-up in the tournament after losing to Saina Nehwal. She then won the All Japan General Championships in December. At 17 years of age, she was the second-youngest player to win the tournament.

She qualified for participation in the end-of-year championships, the Superseries Finals tournament held in December. She won all of her group matches, against (former champion) Wang Yihan, Ratchanok Intanon and Tai Tzu-ying. She lost in the semi-final against Korean player Sung Ji-hyun.

In 2015, Yamaguchi won her first BWF Grand Prix Gold title at the Bitburger Open, where she defeated Busanan Ongbamrungphan in the final. She also finished as the runner-up at the Japan Open Super Series, losing the final to her compatriot Nozomi Okuhara. During the Indonesian Open, she defeated the reigning Olympic champion, Li Xuerui, in the second round. In team competition, she helped Japan win the silver medal at the Sudirman Cup, which marked the country's first-ever silver medal at the event.

Yamaguchi made her Olympic debut at the 2016 Rio Olympics, where she was eliminated in the quarterfinals by her compatriot Nozomi Okuhara. That year, she won back-to-back BWF Super Series titles at the Korea Open and the Denmark Open. She also helped the Japanese team win a bronze medal at the Uber Cup.

In 2017, Yamaguchi won three titles: the German Open, the China Open, and the season-ending Dubai World Superseries Finals. She also finished as the runner-up at the Asian Championships, the Australian Open, the Denmark Open, and the French Open. At the World Championships, she entered as the top seed but was eliminated in the third round. In team competition, she was part of the Japanese squad that won the country's first Asia Mixed Team Championships title. She concluded the season as the year's highest-earning player, collecting US$261,363 from 15 tournaments.

In 2018, Yamaguchi became the world No. 1 for the first time. That year, she was a member of the Japanese women's team that won gold medals at Asia Team Championships, the Asian Games, and the Uber Cup. The Uber Cup title was Japan's first in 37 years. Individually, she won bronze medals at the World Championships and the Asian Games. On the BWF World Tour, she won two titles: the German Open and the French Open, and finished as the runner-up at the All England Open. She capped off her year with a semifinal finish at the BWF World Tour Finals.

In 2019, Yamaguchi became the first Japanese player to win the women's singles title at the Asian Championships. On the World Tour, she secured three titles: the German Open, her first Super 1000 title at the Indonesia Open, and the Japan Open. Her consecutive victories in Indonesia and Japan propelled her back to the World No. 1 ranking on 30 July. She also finished as the runner-up at the Malaysia Open and earned a silver medal with the Japanese team at the Sudirman Cup. The latter half of the season was disrupted by injuries; a lower back injury sustained after the Japan Open limited her preparation for the World Championships, resulting in a second-round exit. She later suffered a right calf injury, forcing her withdrawal from the Korea Open, before ending the season with a semifinal finish at the BWF World Tour Finals..

In a 2020 season shortened by the COVID-19 pandemic, Yamaguchi's primary achievement was winning the Thailand Masters. In team competition, she was a member of the Japanese team that won the Asian Women's team championship.

The following year, in 2021, Yamaguchi competed as the fourth seed at the 2020 Tokyo Olympics, where she lost in the quarterfinals to P. V. Sindhu. On the BWF World Tour, she won two consecutive titles at the Denmark Open and the French Open, and finished as the runner-up at the Indonesia Masters. In team competitions, she was a member of the Japanese squad that earned silver medals at both the Sudirman Cup and the Uber Cup. Yamaguchi ended the year by capturing her first world title at the 2021 World Championships in Huelva, after defeating Tai Tzu-ying in the final. With this victory, she became the second Japanese women's singles player to win the World Championships after Nozomi Okuhara.

In 2022, Yamaguchi successfully defended her world champion title at the World Championships in Tokyo and won her first All England Open title. Her victory at the World Championships made her the first Japanese women's singles player to win consecutive world titles. On the BWF World Tour, she also won the Japan Open and concluded the season by winning the BWF World Tour Finals. Furthermore, Yamaguchi was the runner-up at the Asian Championships and was part of the Japanese team that won a bronze medal at the Uber Cup. In recognition of her performances, she was named the BWF Female Player of the Year.

In 2023, Yamaguchi won five World Tour titles: the Malaysia Open, German Open, Malaysia Masters, Canada Open, and Hong Kong Open. She also finished as runner-up at the China Open, Singapore Open, and India Open. At major individual championships, she secured bronze medals at both the World Championships and the Asian Championships. She also contributed to Japan's bronze medal finishes at the Sudirman Cup and the Asian Games. However, her season was curtailed by a right peroneal tendon injury sustained during the Asian Games in September, forcing her to retire from the match. This injury subsequently led to her withdrawal from the rest of her scheduled tournaments, including the season-ending World Tour Finals in Hangzhou.

After a three-and-a-half-month recovery from a right foot injury sustained in late 2023, Yamaguchi began her 2024 season in January. She finished as the runner-up at consecutive tournaments the French Open and the All England Open. However, she retired during the All England final due to a right hip injury. This hip injury recurred at the Uber Cup in May, where she contributed to Japan's bronze medal. The injury continued to disrupt her Olympic preparations, leading to a withdrawal from the Indonesia Open in June and delaying her return to full-scale training until July, mere weeks before the Olympics. At the 2024 Paris Olympics, she reached the quarterfinals before losing to the eventual gold medalist, An Se-young. Following the Olympics, Yamaguchi secured two titles on home soil at the Japan Open and the Japan Masters. Her season concluded with another injury-forced retirement, this time due to a right calf injury, at the All Japan Championships in December.

Returning from a calf injury that concluded her 2024 season, Yamaguchi's 2025 season was highlighted by her victory at the World Championships in Paris. She secured her third women's singles world title by defeating Chen Yufei in the final (21–9, 21–13). This victory made her the first Japanese player in any discipline to win three world championships titles. On the BWF World Tour, she consistently reached the semifinals in six tournaments she entered, including the three Super 1000 events: the All England Open, the Indonesia Open, and the China Open. She won her first world tour of the year in Korea Open and continues her good form by winning Arctic Open. She also reached the quarterfinals at the Asian Championships and contributed to Japan's bronze medal at the Sudirman Cup.