Top seed Son Wan Ho and second seed Lee Huyn Il remain on course to meet in the Korea Masters final after both player were victorious in their respective quarter-final matches on Friday.
Son booked his place in the last four with a 21-16, 21-17 victory over fellow Korean Ha Young Woong and will next face compatriot Lee Dong Keun, the fourth seed.
Lee needed to work much harder for his victory, though, eventually beating Indonesian eighth seed Christie Jonathan 19-21, 21-12, 21-9 in 63 minutes.
Lee, meanwhile, came through another all-Korean match against Heo Kwang Hee, winning 21-16, 17-21, 21-13 in 62 minutes.
The second seed will face Jeon Hyeok Jin in the semi-finals after the sixth-seeded Korean beat Japan's Kenta Nishimoto 22-20, 7-21, 21-12.