The Principle of Physical Mechanism
In Taijiquan, Yi initiates the chain of action: it directs the muscles to Relax, and Relaxation allows Jin to emerge. When Relaxation and Jin are under refined control, the muscles of any body part can—moment by moment and without fixed order—shift among the four states defined earlier. Upon this foundation, Taijiquan’s physical mechanisms of movement take shape.
These mechanisms diverge sharply—often running counter to habitual movement patterns and reflexes. Consequently, they have long been misunderstood and mystified.
1. The Principle
Within this framework, the mechanisms are identified, defined, and classified into four rules:
- Two energy-conversion rules: governing the exchange between potential and kinetic energy when borrowing External Forces.
- Two coordination rules: regulating the relative positioning and timing of body segments during movement.
Together, these rules describe the physical mechanisms that link structural change, energy transfer, and functional motion.
2. The Definition of Rules
Rule A: Use of Gravity
This rule harnesses gravity—the Earth’s constant pull. While a posture is held at a given height, Relaxing some of the supporting musculature allows the body to drop vertically, converting potential energy into kinetic energy.
The vertical drop naturally turns into horizontal travel as the body follows the path of least resistance. When that momentum wanes, portions of the previously Relaxed musculature enter Tightening to lift the body and restore potential energy, completing the loop of gravitational borrowing.
Rule B: Use of Horizontal Impact
This rule harnesses horizontal impact from external sources—such as an opponent’s push or pull. Consider a swing: a push is absorbed as horizontal momentum, which then carries the body upward along an arc, converting horizontal motion into vertical potential energy. A comparable effect appears in sailing, where wind both drives the boat forward and helps lift it over waves.
Like Rule A, it is a form of power borrowing. Here the direction of conversion is reversed: horizontal impact is transformed into vertical potential energy.
Together, Rules A and B form a closed loop of energy conversion, allowing practitioners to borrow External Forces from any direction.
Rule C: Counter-Movement
Rule C makes explicit what often escapes attention: Counter-Movement. As the body moves in one direction, not all segments advance together; some briefly move in the opposite direction—an asynchronous rhythm commonly observed between the waist and shoulders, or between the torso and the limbs.
This phenomenon stems from variations in inertia, mass, and resistance among the body’s segments.
We encounter Counter-Movement constantly in daily life: take a step forward and the rear foot—and even portions of the torso—briefly lag behind. This contributes to stability. In Taijiquan, the mechanism is deliberately amplified—not merely to steady the body, but to sustain dynamic readiness, enabling instant, seamless redirection of movement.
Rule D: Consolidation
Where Counter-Movement fosters looseness and transient separation among segments, Rule D emphasizes the opposite: an instantaneous mechanical lock across selected joints or muscular regions. This Consolidation creates a continuous transmission path, allowing momentum—often generated by stronger segments, such as the lower limbs and waist—to pass efficiently through regions that do not issue force locally.
Consolidation engages the moment a counterattack begins. Acting as a structural catalyst, it locks the transmission path so that a chosen contact point can deliver force from the whole body with minimal loss.
Taijiquan Framework 