Undefeated China and Japan qualified for the curling mixed doubles semifinals after winning their respective round-robin groups at the Asian Winter Games.

The Chinese pair defeated South Korea 6-4 before smashing Qatar 10-1 on Thursday to keep a clean record after three competition days. The Japanese team also stayed unbeaten after victories over Chinese Taipei and Kuwait on Thursday.

Japanese player Tori Koana said: "We are very happy. We don't need to play qualification games. So it's easier for us to get gold medal."

The remaining two semifinals spots will be decided after two qualification matches that see Hong Kong, China face off South Korea, and the Philippines vie against Chinese Taipei.

On Thursday, the Philippines had a convincing victory over Kazakhstan 11-2 and Hong Kong, China beat Mongolia 9-2 as both placed second in their respective groups with four wins and one loss.

"I think we did well at weight control today. So we are really happy to go into the qualifications," said Dubberstein Kathleen Sumbillo of the Philippines.

South Korea beat Kyrgyzstan 14-3 and Chinese Taipei stunned Thailand 12-0 to rank third in their respective groups with a 3-2 record.