Eight Gates: The eight gates (ba men) or eight skills are methods used in taijiquan. They appear in many movements within taijiquan forms and in push hands, sometimes alone and often in combination. The eight are sometimes practiced as a simplified fixed stance or walking form. In push hands, the basic two-handed circle pattern is performed cycling through peng lu ji ahn. Note that refined skill or refined energy is referred to as "jing" and it is often convenient to refer to the skills below as peng jing, lu jing ...
Peng - Upward/outward expression of buoyant energy. Also, a feeling of connected fullness through the body that should maintained continuously during taijiquan practice.
Lu - Rollback. A leading, but not pulling kind of energy often used to counteract an opponent's peng jing. A common mistake in taijiquan practitioner is to block an opponent's force rather than roll it back and lead them into a vulnerable position.
Ji - Squeeze. This jing crowds and opponent. A common use of ji jing happens when an opponent rolls back the force of one of your arms. You crowd in and squeeze them with ji jing with the other hand or a combination of hands.
Ahn - Sinking down. An application of ahn jing is breaking an opponent's ji jing - use this vertical force to break their horizontal force.
Ts'ai - Pluck. This can be used with lu jing to draw an opponent into vulnerability and suddenly apply shocking "cold power" with ahn. Some chin na (seizing and controlling for joint locks) is said to employ ts'ai.
Lieh - Split force. Two-direction force. It is often thought of as force acting linearly in two opposite directions or circularly around two opposite sides of a circle. Many applications involving joint locks and throws utilize lieh jing. Some teachers are of the position that many strikes utilize lieh because, for example, one arm counteracts the other by using opposite directions in a punch (i.e., punch with right fist, pull back left elbow).
Jou - Elbow strike. The point (piercing elbow), flat of the forearm, or back of the upper arm may be used in a variety of directions.
Kao - Strike with the body. Common strike parts include shoulder, hip, back and chest.
Five Skills: (some of this material is paraphrased from Jin Taiyang's article in The Chen Style Journal Vol. 5, no. 1). These five skills are added to the eight above to describe the "13 postures" of Chen Taiji.
Teng - Jump, rise, as in agile footwork and evading an attack to the legs. Example: jade maiden works shuttles.
Shan - Dodging, evade, quick avoidance, flash like lightening. Example: Flashing turn to back.
Zhe - Bend, fold
Kong - Leave empty, used in leading into emptiness
Huo - Change, unpredictability
Zhan - Contact your opponent with some part of you against some part of them.
Nian - Stick to your opponent with a ... sticky feeling.
Lian - Follow them continuously to many places, to any place they go.
Sui - Follow them directly to where they are going.
Bui dao bui dun - Not away (don't detach), not against (don't use force against force).
Da Shuai Chin Na: One perspective in Chinese martial arts is that a complete martial art must contain strikes (da), throws (shuai), and joint locks (chin na - seize, control).