1. Wardoff Jing (Peng Jing)
Wardoff jing is a strong yang jing that is used offensively even in defense. In principle, it behaves like a large rubber ball—when pressure is applied, it compresses, and when a certain point is reached, it bounces the outside force away. The opponent's force is often directed upward; as you lift his attack the way water lifts a boat. This jing is often emitted at maximum strength in coordination with the sound ha. It may be done at all ranges, and is often used to bounce the opponent away. This application is forceful, but not directly destructive.
Defensively, this jing absorbs the opponent's attack and then bounces him away. In this application, your forearm does not generally come into contact with the opponent's body, but instead functions through his attacking arm. Specifically, you absorb some of the opponent's force either at the very beginning or at the end of his attack, and give the force back to him through his stiff arms (also read borrowing jing). Wardoff is commonly used against a punch, in which case it directs the attack upward and seals the arm.
Offensively, wardoff is used as a strike, most often to the opponent's chest or arm. When this jing is used to attack the chest, some other neutralization is usually used first in order to set up the attack. When this jing is used to attack the opponent's arm, his attack must be neutralized downward and sealed first.
In order to bounce the opponent away, you must first destroy his root to upset his stability and balance. This is done by directing the force of your wardoff slightly upward or sideward.
Your body must be sunken in order to build up your own root, stability, and upward power. Wardoff is sometimes done as a sort of double technique. First, apply a small push to the opponent or deflect his attack and lead him to an unbalanced position. If he rises a little and his root becomes unstable, you should immediately apply a second, stronger push to knock him away. If, on the other hand, he resists and pushes forward, withdraw slightly and lead his momentum upward. As soon as you succeed in leading him, immediately emit your force to knock him away.
As with most of these techniques, muscular force will predominate in the beginning, but as you gain skill, the reliance on muscles will lessen and you will do these techniques with arms that are more and more relaxed. Indeed, you will find that you cannot really do these techniques well with tensed muscles because this interferes with accurate sensing and precise control.
Training for Wardoff Jing
There are several ways to train wardoff jing. A good way is to use a bag, first a light one and later, heavier ones. You can practice striking with wardoff, and you can practice pushing. To do the latter, you can place your forearm against the bag and push it slightly to get it moving. "Catch" the bag on your forearm as soon as it starts to move toward you, and immediately bounce it away. You can swing the bag and "catch" it near the end of its swing and bounce it, or move the bag around in circles and use wardoff to redirect it sharply away from you.
You can also practice wardoff on a partner. When you do this, it is best for the person being pushed to protect his chest with his forearms to prevent injury. Another exercise is for one person to stand in the wardoff position, and the other to push the extended forearm with both hands in a somewhat stiff-armed fashion. The first person either absorbs some of the force, directs it into his root, and then bounces it back, or else emits force just as the other person is about to push.
When doing wardoff, the body must be centered and stable, and your yi of attacking must be farther than the target. Yi, qi, and jing must be balanced among the attacking arm, the other arm, and the rear foot.
2. Drilling Jing (Zuan Jing, 鑽勁)
Drilling jing is an offensive jing that twists as it penetrates. When your hand touches the opponent's body, your arm and hand rotate clockwise or counterclockwise in a screwing motion, which makes the power penetrate more deeply than with a regular attack.
The power, which is generated by turning the waist and shoulder, is usually directed forward, although it can also be used sideward. The fist, finger, or knuckle is usually used for attack, frequently against vital cavities. The muscles must be tensed somewhat to direct the jing and to ensure that it penetrates, and also to protect the hand against injury. Also, your yi must be concentrated inside his body in the organ or cavity being attacked. Drilling jing is also occasionally used to pull your arm out of the opponent's grasp. Here too the shoulder and waist are the sources of the jing.
Because drilling jing is used in both external and internal styles, many training methods have been developed. One of the common ways used in external styles is to drill your fist or knuckle into a bucket of mung beans. (Mung beans are used because of their medicinal properties.) With practice, you will be able to drill deeper and deeper. Later, sand can be used in place of beans. Punching bags are also popularly used for drilling training.
Taiji uses less muscle than external styles, so the training approach is different. One method uses a thick layer of soft material, for example, tissue paper on a table. The fist is pushed down with a screwing motion. The muscles should be relaxed as the yi strives to extend the jing to the surface of the table. When you can bounce the jing off the table, increase the thickness of the material. The thicker the material is, the greater the drilling power required. It is important to also do this exercise horizontally.
3. Breaking Jing (Duan Jing, 斷勁)
Breaking jing is used for breaking the opponent's bones or joints. Forward breaking jing is commonly used to break ribs, and sideward or downward breaking jing is used to break limbs. The yi is concentrated slightly beyond the target.
This is different from the penetrating drilling jing, where the yi is concentrated deep into the organ being attacked. If you have ever chopped wood, you should understand how to use this jing. When you are chopping a branch, if you concentrate and aim a bit beyond the branch, you should have little trouble chopping through it. Also, if just before the axe reaches the wood you suddenly increase your speed and jerk the power out, you will find that you can cut the branch without using much power.
In breaking, when the qi and jing reach the target, the muscles must be tensed so that all the power is expended in the target. In taijiquan, the time that you are tensed is kept as short as possible. This allows you to remain relaxed and make your breaking jing sharper and more concentrated. A great deal of speed must be developed. Once the target is hit, the speed stops, but the yi continues on through. It is important that the yi be focused only slightly beyond the target. If you focus too far beyond the target, your jing will pass uselessly through it. There is also a danger of injuring yourself. Because you normally tense your muscles only a short distance before the focus point, if the focus is too far beyond the target, you will be relaxed when you hit. This will allow the power to bounce back to you and injure your arm or fist.
Many training methods are used both in the external and the internal styles. The most common way to train sideward breaking jing for use on the opponent's elbow is with a wooden rod about an inch and a half in diameter.
Some people train with branches on trees. In the beginning, wrap the rod or branch with cloth to avoid injuring your arm. When applying jing, the root must be firm. The power is generated from the legs and guided by the waist onto the target. (See also the section on sideward hooking jing.) Punching bags are also used, especially for training forward breaking jing. To break ribs your yi must be centered a little past the ribs, so aim your techniques a few inches inside the bag. Remember, yi is the most important factor in breaking.
(The above excerpt is from Tai Chi Chuan Martial Power: Advanced Yang Style by Dr. Yang, Jwing-Ming.)