See also: [[Misc./Tai Chi/Chen Style|Chen Style]] and [[Misc./Tai Chi/History|History]] for how Chen Wangting folded Yijing/bagua theory into the art in the first place. **Peng, Lu, Ji, An** (掤, 捋, 擠, 按) are the four primary "energies" or "jins" (勁, *jin* — trained internal force, distinct from raw muscular strength *li*, 力) of tai chi. They're the cardinal four of the **Eight Gates** (八門, *ba men*), a framework mapping eight ways of directing force in push-hands (tui shou) and form practice onto the eight trigrams (bagua) of the Yijing — the same theoretical grounding Chen Wangting used to systematize the art. The four primary energies sit on the cardinal directions; four corner/secondary energies — Cai (採, pluck), Lie (挒, split), Zhou (肘, elbow strike), Kao (靠, shoulder/body bump) — sit on the diagonals. All eight together are sometimes just called the "eight energies" (八勁, *ba jin*). Peng, Lu, Ji, An are considered foundational — they're trained first, and are the four moves that make up **Grasp the Bird's/Sparrow's Tail** (攬雀尾, Lan Que Wei), the sequence that opens most tai chi forms and is often treated as the form's tactical core in miniature. ## The four energies ### Peng (掤) — Ward-off Usually translated "ward off," though "outward supportive strength" is closer to the feel of it. Peng is expansive, buoyant, spring-like — often described as a balloon or ball that can't be flattened: pressure applied anywhere on its surface is met with resilient, structural resistance rather than rigid blocking or collapse. Peng is treated as the root energy of the whole art — not one technique among others but the underlying condition that has to be present for the other three (and arguably all eight) to work. Several sources describe tai chi itself as fundamentally "peng jin boxing": without peng, push-hands has nothing to yield with, redirect, or issue force through. ### Lu (捋) — Roll-back A yielding, redirecting energy — the yin counterpart to peng's yang. Lu receives an incoming force (typically an opponent's An/push) and leads it past the centerline rather than opposing it head-on, drawing the opponent's weight and root forward and off-balance. It's often glossed as "creating a vacuum" that the opponent's own momentum falls into. ### Ji (擠) — Press/Squeeze Often translated "press," though "squeeze" is closer to the original sense. Ji is a compact, forward-issuing energy that closes distance and fills the gap that Lu just opened in the opponent's structure — attacking through the opening before they can recover or reorganize. Where Lu empties, Ji fills. ### An (按) — Push Completes the four-part cycle: a forward-and-downward pressing/pushing energy, typically the finishing, uprooting release in the Peng→Lu→Ji→An sequence. ## Why "energy" and not just "technique" Jin isn't a fixed hand shape or a single move — the same jin can show up in many different postures, and a given posture in the form can express more than one jin depending on how it's trained. That's part of why practitioners describe peng as "something better felt than described": it's a quality of connected, whole-body structure and intent, not a discrete motion to imitate visually. ## Sources consulted - [The Eight Gates of Taichi — Modern Wushu Wiki](https://modern-wushu.fandom.com/wiki/The_Eight_Gates_of_Taichi) - [Understanding the Eight Energies of Tai Chi — Tai Chi Basics](https://taichibasics.com/eight-energies-of-tai-chi/) - [The Eight Energies Of Tai Ji Quan — Gwong Zau Kung Fu](https://gwongzaukungfu.com/en/the-eight-energies-of-tai-ji-quan/) - [Tai Chi's 8 Gates: Decoding Peng, Lu, Ji, An for Balance & Internal Power](https://www.taichiwuji.com/blog/tai-chi-8-methods/) - [The Four Essential Energies of Tai Chi — Peng, Lu, An, Ji — Chen Tai Chi Academy](https://chen-taiji.com/the-four-essential-energies-of-tai-chi-peng-lu-an-ji-a-genius-perspective/) - [Peng, Lu, Ji, An — Blackwater Tai Chi](https://www.blackwatertaichi.com/blog/peng-lu-ji-an) - [On Tai Chi Peng Jin — Thoughts On Tai Chi](https://taichithoughts.wordpress.com/2013/06/09/on-tai-chi-peng-jin/) - [A Journey Through the Jins — Ward-off (Peng Jin) — Tai Chi Internal Arts Union](https://www.taichiunion.com/news/a-journey-through-the-jins-ward-off-peng-jin/) - [Peng, Jin, and Li — Chuck Row Tai Chi](https://www.chuckrowtaichi.com/Peng.html) - [Peng, Lu, Ji, An: Grasping the bird's tail — The Tai Chi Notebook](https://thetaichinotebook.com/2015/09/10/peng-lu-ji-an-grasping-the-birds-tail/) - [Grasp the Sparrow's Tail and the 4 Primary Jins — Metrowest Tai Chi](https://metrowesttaichi.com/articles/grasp-the-sparrows-tail-and-the-4-primary-jins/)