Several players had to face their compatriots at the Badminton World Federation Fuzhou China Open as the semi-finals were decided at the Haixia Olympic Sport Centre.
In the women's singles, Nozomi Okuhara eased past her Japanese compatriot Sayaka Takahashi 21-4, 21-10.
Joining her in the semi-finals of the World Tour Super 750 event will be China's He Bingjiao who battled past third seed, PV Sindhu of India, 21-17, 17-21, 21-15.
Another Chinese player, Chen Yufei, also made the last four as she triumphed 15-21, 21-9, 21-11 over Thailand's former world champion Ratchanok Intanon.
Yufei's opponent will be Spain's Carolina Marin as the fifth seed, the reigning world and Olympic champion, defeated American Beiwen Zhang 21-11, 21-13.
In the mixed doubles, China supplies three of the last four pairs in the competition.
Top seeds Zheng Siwei and Huang Yaqiong will have to face compatriots He Jiting and Du Yue in the semi-finals after overcoming Thailand's Dechapol Puavaranukroh and Sapsiree Taerattanachai, 21-10, 19-21, 21-11.
He and Du defeated third seeds Tontowi Ahmad and Liliyana Natsir from Indonesia in the quarter-finals, 21-18, 21-19, to progress.
In the other side of the draw, Japan's Yuta Watanabe and Arisa Higashino are the only non-Chinese team to qualify for the semi-finals after beating South Korea's Kim Won Ho and Baek Ha Na, 21-19, 26-24.
The Japanese duo will have to face second seeds, Wang Yilyu and Huang Dongping, next.
Wang and Huang dropped their first game against Indonesian opponents, Praveen Jordan and Melati Daeva Oktavianti, but fought back to win 18-21, 21-16, 21-14.
Elsewhere, top seed Kento Momota, the world champion, is through to semi-finals of the men's singles.
The Japanese player beat seventh seed, Son Wan Ho of South Korea, 21-17, 21-14.
Momota now faces sixth seed Chen Long from China, the Olympic gold medallist at Rio 2016, who beat Anders Antonsen of Denmark, 21-18, 21-16, in the quarter-finals.
Chinese Taipei's Chou Tien Chen is also through as the fourth seed overcame fifth seed, Kidambi Srikanth from India, 21-14, 21-14.
Second seed Shi Yuqi will face Chou in the semi-finals as he beat Indonesia's Anthony Sinisuka Ginting.
Shi lost the first game but recovered to advance, 16-21, 21-14, 21-14.
Indonesia's top seeds, Marcus Fernaldi Gideon and Kevin Sanjaya Sukamuljo became the first semi-finalists in the men's doubles event.
They beat Danish pair Kin Astrup and Anders Skaarup Rasmussen, 22-20, 21-17.