Jess, the applications are pretty much the same (specially in the holds) what about the internal mechanics of Pi Quan and Somen Uchi?. When you had them both, did your Somen Uchi came out with Pi intention in mind?
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Reading further I think you answered that:
One of the things that Xing Yi teaches, is to use Pi Quan (Shomen Uchi) as a way to draw out and engage someone, often its used so that the other guy blocks and you can then seamlessly switch to a technique of some kind. The striking surface can be anywhere on the arm, hand, elbow, hitting upward, down ward, sideways (yokomen Uchi) etc.
This is the reverse of the average Aikido way of doing things, where you await Uke's attack and then throw him. In XIng Yi, Nage attacks first, draws out Uke's response and then finishes him off.
Cool post
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