The South Korean won in straight games at the Tokyo Metropolitan Gymnasium as he looks to win his first title since ascending to the summit of the rankings in May.

Lin, China's Olympic gold medallist at Beijing 2008 and London 2012 as well as a five-time world champion, was always going to be a tough prospect but the 33-year-old was well beaten.

Twenty-nine-year-old Son, who won World Championship bronze in Glasgow last month behind Lin's silver, came through 21-15, 21-15.

He will now meet Denmark's reigning world champion Viktor Axelsen in the last four after the third seed won his last eight clash 21-17, 21-17 against India's Srikanth Kidambi.

China's second seed Shi Yuqi knocked out another Indian as he beat Prannoy Kumar 21-15, 21-14 to advance.

His reward is a clash with Malaysia's triple Olympic silver medallist Lee Chong Wei.

The fifth seed beat the fourth seed, Chou Tien-chen of Chinese Taipei, 21-11, 15-21, 21-19.

In the women's competition at the Super Series event, a semi-final between the reigning Olympic and world champions was booked.

Rio 2016 gold medallist Carolina Marin of Spain, the fifth seed, won her quarter-final 21-18, 21-15 against Japan's second seed Akane Yamaguchi.

She will now meet another home player as unseeded world champion Nozomi Okuhara knocked out American eighth seed Zhang Beiwen 21-16, 23-21.

The other semi-final will be an all-Chinese affair after sixth seed He Bingjiao and the unseeded Chen Yufei both progressing.

He knocked out home hope Sayaka Takahashi, coming from behind to win 14-21, 22-20, 21-16.

Chen, a bronze medallist at the World Championships, defeated another Japanese player as Aya Ohori was beaten 21-13, 10-21, 21-19.

The semi-finals will be played in the 2020 Olympic host city tomorrow.