According to the Gyokko Ryu and Koto Ryu densho, Yao Yù hǔ (Yo Gyokko, 姚玉虎) was the founder of the Gyokko Ryu in China.
She taught the art to military commander Zhang Buren (張武連).
Buren taught his son, Zhang Busho (張武勝) who later, during the Han Dynasty fled to Japan due to politics.
Some legends say that Busho was a General from Baekje, a Korean kingdom in the southwest of the Korean peninsula and that when he went to Japan he took the remnants of his army with him. With these men came the arts of Koshijutsu, Hichojutsu, Naginatajutsu, Chinese Boxing, etc. These arts spread throughout Japan and legends say the descendants of Zhang Busho and his men are the Sakanoue clan of Japan. This clan is famous for producing Sakanoue no Tamuramaro (坂上 田村麻呂, 758 – June 17, 811), a general and shōgun of the early Heian period of Japan.
According to the Shoku Nihongi, an official historical record, the Sakanoue clan is descended from Emperor Ling of Han China.
The Sakanoue clan’s family tree shows that Tamuramaro is a 14th-generation descendant of Ling.
Other research traces the origins of the Sakanoue clan from the Asian mainland, possibly through Baekje (Korea).
So, while the art’s roots may lay back in China, we are talking about approximately 2,000 years ago.
It is very highly unlikely that any form of the original Gyokko Ryu is still active in China.
I myself lived in China for several years researching Takamatsu Sensei and martial arts in general. I never came across any direct link to any of our Ryu with any martial art in China. Our Ryu were inspired by teachings from China but were undoubtedly very Japanese in their practice and development.
Bujinkan Kokusai Renkoumyo
Above and below images depict Sakanoue Tamuramaro