Lu (捋)

Lu (捋, sometimes written Lü) is the second of the four cardinal gates of Taijiquan — the yielding, redirecting energy that captures an incoming force and leads it past the body into a corner. Where peng (掤) receives an attack into a buoyant structure, lu yields and redirects: the partner's force is accepted, the line of attack is neutralized, and the force is drawn past the practitioner's centerline so that the partner overcommits and floats. Lu is the exhale of which peng is the inhale; the two together describe the receiving half of the four-cardinal cycle.

Lu is conventionally translated roll-back, and the translation captures the curving, drawing-past quality of the energy. But like all eight gates, lu is fundamentally a jin — a trained internal force — not a choreographed motion. The practitioner who has only the shape of lu has only retreat. The practitioner who has lu jin has a trained energy that uses the partner's commitment against them, dissolving incoming force without losing structure.

Mechanically — how lu is generated

Lu is not produced by pulling the partner's arm back with the hands. The hands, in correct lu, are nearly stationary — they make contact, capture the partner's forearm or wrist, and stay there. What moves is the body: weight transfers fully to the rear foot, the kua (胯) releases on the receiving side, the yao (腰) turns, and the body withdraws under the stationary hands. The classical phrasing is that the practitioner presses the front foot into the ground to move the body away from the hands, rather than dragging the hands back with the body.

This distinction is what separates lu from a simple retreat. If the hands move back with the body, the partner's structure is not used — they simply step forward and re-engage. If the body moves while the hands hold their line, the partner's forward commitment is captured by the contact and drawn past the centerline — they overextend and lose their root, while the practitioner has done nothing but release a kua and turn a waist. [1]

Three structural conditions make this possible:

• Song kua (鬆胯) on the side the weight is settling into — without this, the lower body locks and the retreat becomes a stumble backward rather than a clean withdrawal under control.

• A sinking elbow at the contact point — without this, the upper body lifts as the lower body settles, and the hands are pulled out of contact.

• A turning yao (鬆腰) — without this, the redirection has no angular component, and the partner's force passes straight through rather than off to the corner.

When all three are present, lu happens inside the body and the partner only sees a slight rotation. They do not see the work that has just dispersed their attack.

Lu in the form

Lu first appears in the long form as the second posture of Grasp Sparrow's Tail — the canonical peng → lu → ji → an cycle that opens every Yang form's substantive content. The student first meets lu as a sequence position and a shape: forward hand palm-up at the partner's forearm just below the elbow, rear hand at the partner's wrist or palm-up under the partner's elbow, weight transferring fully to the rear foot while the kua releases.

Beyond Grasp Sparrow's Tail, lu is present as a quality in many other postures — the Cross Hands transitions, the Carry Tiger Over Mountain preparation, the small redirective turns before postures like Parry and Punch. The student who learns to see lu rather than just name it begins to recognize the same energy operating in places the form does not label.

Lu in push hands

In fixed-pattern push hands, lu becomes the trained answer to an incoming push. The drill teaches the receiving mechanic at slow speed: the partner pushes, the practitioner's contact captures their forearm, the kua releases, and the body settles back as the partner is led past the centerline. Done correctly, the partner falls into the lu — their own commitment, not the practitioner's pull, is what carries them off their root.

In free pushing hands, lu becomes direction-independent. The energy is no longer attached to a particular hand shape or weight transfer; it is the trained quality of capturing-and-redirecting applied to whatever the partner offers. At this stage lu sets up its natural follow-ups:

• Ji (擠), press — the most common sequel. Lu draws the partner in and off-balance; ji issues forward into the gap the redirection has created.

• An (按), downward press — when lu's redirection has floated the partner (their root is gone but they are still vertical), an can sink them through the structure their feet have momentarily abandoned.

• Lie (挒), split — the corner-gate alternative to lu when receiving: rather than redirecting along a single curve, split the partner's structure along two opposing vectors at once.

What goes wrong with lu

Several characteristic errors mark immature lu, and each illustrates by contrast what mature lu requires:

• The wiggly-worm retreat. The hands give up structure under any pressure at all — they simply collapse aside, and the partner reaches the practitioner's centerline without interruption. There was no lu; there was only avoidance. The corrective is peng inside the lu: lu without internal peng collapses into nothing.

• Pulling with the arms. The hands drag back, the partner is not engaged through the contact, and the kua does not release. The body has not moved; the arms have. The corrective is the press-front-foot-into-ground mechanic — let the body retreat under stationary hands.

• Losing the contact. The partner's structure is dropped at some point in the redirection — the practitioner stops listening through the contact, and the partner regains their root mid-motion. The corrective is ting jin maintained throughout: lu requires continuous reading of where the partner's center is going.

• Over-rotation. The yao turns too far, opening a flank to the partner's free hand. The corrective is just enough turn to draw the line past centerline, no more.

Related concepts

Ba Men (八門) — the Eight Gates; lu is the second

Peng (掤) — lu's complement; the gate that must be present inside lu

Ji (擠) — what lu sets up; the press into the gap lu creates

An (按) — the downward press that frequently follows lu

Song (鬆) — without song kua, no lu

Sources

[1] Adam Mizner, Discover Taiji curriculum — the formulation that lu is generated by pressing the front foot into the ground to move the body away from the hands, rather than pulling the hands back with the body, is a structural point repeated across his transmission of the cardinal gates.

[2] The classical Thirteen Postures Treatise (十三勢歌訣) lists lu second among the four cardinal energies (四正勁), establishing its place between peng (the first gate) and ji (the third).

[3] Yang Chengfu (楊澄甫), Taijiquan Shi Yao — the Ten Essentials' emphasis on song the yao (point 3) and sink the shoulders and drop the elbows (point 5) names the structural preconditions on which lu depends as directly as it names those for peng.