It came as Japan also won two gold medals and Denmark and China earned one apiece in the Innogy Sporthalle.

Sixth seed Chou required just 34 minutes to defeat compatriot Tzu Wei Wang 21-16, 21-14 in the men's singles.

It came after 14th seed Wang shocked China's Olympic champion Chen Long in yesterday's semi-final.

The tournament proved a difficult one for Rio gold medallists as Spain's women's singles winner Carolina Marin was forced to withdraw before her final through injury.

This handed an automatic victory to Japan's second seed Akane Yamaguchi.

Yuki Fukushima and Sayaka Hirota also secured a Japanese victory in the opening contest of the day courtesy of a 15-21, 21-17, 21-15 women's doubles win over Chinese fifth seeds Huang Dongping and Li Yinhui.

Kim Astrup and Anders Skaarup Rasmussen of Denmark won the corresponding men's doubles event.

The fourth seeds won an all-Danish final against Mads Conrad-Petersen and Mads Pieler Kolding, 21-17, 21-13.

China avoided a gold medal blank at the Grand Prix Gold level event by triumphing in the last final of the day.

It was not the expected result, however, as Zhang Nan and Li Yunhui beat top seeds Lu Kai and Huang Yaqiong 22-20, 21-11 in the mixed doubles.