柳延星
In 2015, he and Kim Gi-jung won the Korea Masters Grand Prix Gold tournament in the men's doubles event. In the final round they beat Ko Sung-hyun and Shin Baek-cheol with the score 16–21, 21–18, 21–19. They also won the China Open Super Series Premier tournament, after beat Chai Biao and Hong Wei in the straight games. In 2016, they also won the Superseries Premier tournament in Malaysia. He and his partner beat the third seeded from China in the quarterfinal round, and the world No.1 pair, Lee Yong-dae and Yoo Yeon-seong in the semifinal. In the final round they beat Chai Biao and Hong Wei with the score 21–19, 21–15. He and Kim Sa-rang also competed at the Summer Olympics in the men's doubles event. They lost in the quarterfinal round, defeated by Fu Haifeng and Zhang Nan of China with the score 21–11, 18-21 and 22–24. After the Rio Olympics, he decided to retire from the national team, and on 31 October 2016, BWF sites officially announced his retirement. However, in 2018 he has since played as an independent player separate from the BKA with the Malaysian former world number one, Tan Boon Heong, in the Macau Open and Korea Masters.