Wow...this thread is very interesting
The xingyi shown in the clip that DeVere posted is Song style Xingyi: Short, sudden strikes (one-inch power), high posture, very powerful.
The variations between styles depend on the branch (Hebei, Shanxi, Henan), and the families of each branch ), like Song, Che, Bu, Shang Yunxian, etc. Each head master took what worked for him, and developed their own family Xingyi after that. That's why there are so many variations. But all of them fall into the three main branches.
About that loooong forms list that DeVere posted, we ned to update it, because I have seen a few more forms (like a dozen)
But, the Five Elements and the Twelve Animals, together with the Lianhuan (Five Element Linked Forms) and the Zha Shichui are mandatory in all Hebei and Shanxi styles, regardless of family.
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