Hello,
I want to point out that YMAA does in fact practice Chin Na in Groundfighting. This was first rationalized in the early generations of YMAA under Paul Arsenault and Joseph Faulise in the YMAA produced book titled Chin Na in Groundfighting. This book was a great resource, but did not include many of Master Yang's Chin Na techniques. What the book did was show how Chin Na theory can be applied to Groundfighting.
I frequently teach Chin Na in Groundfighting seminars at the YMAA Boston Headquarters as this is slowly becoming a topic of interest again within the YMAA community. There is a possibility that YMAA publications will be considering my request to write a book and produce a DVD that incorporates Master Yang's Chin Na techniques in Groundfighting. All this is a possibilty of course and I am hopeful that it will materialize in the future so as to address the topic of how Kung Fu applies Chin Na on the ground.
There is no doubt in my mind that Chin Na on the ground existed due to the fact that the transmission of Kung Fu from China to Japan resulted in JuJitsu which heavily emphasized locks on the ground even prior to the Ne Waza revolution brought to light by Jigaro Kano within the realm of Judo.
Jigara Kano only recongnized these ground techniques due to the fact that at his prime and the period of Judo's recogniton as Japan's national martial art/sport Kano's school was challenged by a small unknown JuJitsu school called the Fusen Ryu style which emphasized Chin Na/submissions on the ground.
Jigaro Kano's Judo students lost 13 out of 16 matches to this Fusen Ryu school and not on points. The Fusen Ryu students submitted Kano's students by dragging them to the ground and applying Chin Na locks/chokes! Kano respected this school and allowed it to integrate the Ne Waza (ground techniques) into the Judo curriculum. Mitsuya Maeda A.K.A Count Koma was of this generation and passed the Ne Waza and Tachi Waza (throwing techniques) on to the Gracies and hence the birth/reconstruction and evolution of BJJ (Brazilian Jiu Jitsu).
This Fusen Ryu style evolved out of Chin Na in Groundfighting carried over from Chinese Kung Fu. There is a style of Kung Fu that does fight specifically on the ground named Dog Kung Fu, i.e. Góuquán, i.e Dishuquan a Kung Fu style from China. This is a southern style of Chinese boxing that specializes in takedowns and ground fighting.
Most Kung Fu styles have similar roots in regards to techniques and areas of expertise. Even though Shuai Jiao emphasizes throws on the battlefield, many Kung Fu styles developed aspects of grappling as this is an obvious area of martial arts that could not have been overlooked by all martial artists in 3,500 years of CMA development. Many styles had simply ignored it or refused to train it, yet many did continue to train it and pass it along as evidenced from the mention of the previous styles.
YMAA has always been progressive in understanding and interpreting the martial arts due to the scientific and open minded thought patterns of our great mentor Master Yang Jwing-Ming. Chin Na in groundfighting is a topic that we have addressed for many years and it is my personal goal to further this area of training within YMAA and help it to progress forward as a funtional part of the curriculum eventually.
Keep an eye out for these Chin Na Ground Control seminars on the YMAA Boston website from time to time and remember to research, analyze, share, and keep an open mind so we as a martial arts community can work together in harmony and peace which is the highest level of human nature.