There are interesting facts about the origin of Chen Style Taijiquan closely related to Shanxihongdong Tongbeiquan. The Chens family moved to Henan from Shanxi, and a member of the Chens family move back to Shanxi Hongdong and taught the locals Tongbeiquan around 1770 AD. The following links are part 1 and 2 of a video posted by a Japanese:
山西洪洞通背拳 その1(17:01)
山西洪洞通背拳 その2(4.44)
The performer is Li Guo Suo (1950-), who published a book on Shanxi Hongdong Tongbeiquan in 2016.