Shanghai: The two best badminton players in the world will battle it out in Sunday's final of the Asia Championships when title-holder Kento Momota faces Shi Yuqi.
The women's decider in the Chinese city of Wuhan is another Japan versus China showdown with Akane Yamaguchi taking on He Bingjiao.
The men's clash is a repeat of last year's World Championships final, when Japan's top-ranked Momota defeated Shi.
World number one Momota eased through his semi-final with a comprehensive 21-18, 21-8 victory over Vietnam's unseeded veteran Nguyen Tien Minh on Saturday.
The 36-year-old Nguyen felt he could have pulled off a shock.
"It would have been 19-18 for me in the first game and I am quite sure I would have won if not for a broken string in Momota's racquet catching me off-guard and the shuttle fell in my court," said Nguyen.
Shi, China's world number two, saw off Taiwan's Chou Tien-chen 22-20, 21-18 in the men's other semifinal.
In the women's draw, Japan's third-seeded Yamaguchi stunned top seed Chen Yufei 15-21, 21-16, 21-17 to book her place against Chen's fellow Chinese He.
"I was runner-up in this tournament last year and had high expectations of winning," said the beaten Chen.
"It is disappointing to go out at this stage. Yamaguchi kept coming back and my fitness let me down." The fifth-seeded He won her all-Chinese semi-final against unseeded Cai Yanyan 8-21, 21-12, 21-17.