Every force has an equal and opposite counter-force. The foot presses against the ground — the ground presses back and drives the body. That is why a strike does not arise in the arm: it begins at the foot and runs as a chain through the whole body.
If a body A exerts a force on a body B, then B exerts an equal and opposite force back on A. For Yiquan this is background, not doctrine — neither Wang Xiangzhai nor Yao Zongxun cites Newton. But the principle explains the central mechanics soberly, entirely in the spirit of demystification.
If every force has an equal counter-force — shouldn’t everything then stand still? No. Anyone who thinks so is adding two forces that must not be added at all.
Action and reaction act on different bodies: one on the ground, the other on the person. For the body only the force on it counts — and that is exactly what drives it. This is why walking works. And why Fa Li works.
Force does not arise in the arm. It begins as pressure against the ground and is handed upward step by step through functional force pairs — “body like a hammer, arms like nails”. Tap a step.
Yiquan often speaks of counter-forces — but two different things are meant. Both obey Newton, yet only one moves the body. Yiquan trains both: the internal pre-tension builds the elastic ball, the external ground reaction delivers it as force.
Four of Yiquan’s tools can be read as work on the reaction force — from standing to contact with an opponent.
A firm, permeable stance maximises the usable ground reaction. Without a root the reaction runs into nothing.
Deliberately generating balanced counter-tensions oneself — one’s own “counter-force” supports the force instead of braking it.
The explosive issuing of force: a short thrust against the ground — the reaction springs as a wave through the chain to the hand.
Not blocking the opponent’s thrust but taking it up on the diagonal and redirecting it — the same mechanical picture, in fighting.
Action and reaction do not cancel out — they act on different bodies. That is why the ground carries every strike: force begins at the foot, not in the arm.