Qi's Role in Taijiquan
By Dr. Yang, Jwing-Ming
Normally, it takes at least three years to learn the taijiquan sequence and to circulate qi (energy) smoothly in coordination with the breathing and postures. You should then learn to transport qi and develop qi balance. Even after you have accomplished this, there is still more to learn before you can be considered a proficient taijiquan martial artist. You must learn to strengthen your qi through practice, you must develop a sense of having an enemy in front of you during the sequence, and lastly, you must learn how to train jin (emitting power) during the sequence.
Dr. Yang demonstrates the posture "Step Back and Repulse the Monkey" (Dao Nian Hou) 倒攆猴*
Qi's Role in Taijiquan
In taijiquan, qi plays a major role in jin. When qi is strong and full, then the jin will also be strong. An important way to strengthen and extend your qi is to practice the sequence slower and slower. This is the yin aspect of taijiquan practice, which helps you to build both a strong, concentrated mind and internal qi. If it usually takes 20 minutes to finish the entire sequence, increase the time to 25 minutes, then 30 minutes, and so on. Do not add any more breaths. Everything is the same except that every breath that is used to lead the qi gets longer and longer. In order to do this you must be very calm and relaxed, and your qi must be full like a drum or balloon, first in your abdomen and later in your whole body.
If you can extend a sequence that normally takes 20 minutes to one hour, your qi will be very full and fluid, your mind calm, and the postures very relaxed. When you do the sequence at this speed, your pulse and heartbeat will slow down, and you will be in a deep self-hypnotic meditative state. You will hardly notice your physical body, but instead you will feel like a ball of energy. When this happens you feel you are transparent.
Even when you can do the form very well, it may be dead. To make it come alive you must develop a sense of enemy. When practicing the solo sequence, you must imagine there is an enemy in front of you and you must clearly feel his movements and his interaction with you. Your ability to visualize realistically will be greatly aided if you practice the techniques with a partner. There are times when you will not use visualizations, but every time you do the sequence your movement must be flavored with this knowledge of how you interact with an opponent.
"Single Whip" part 1 (Dan Bian) 單鞭*
The more you practice with this imaginary enemy before you, the more realistic and useful your practice will be. If you practice with a very vivid sense of enemy, you will learn to apply your qi and jin naturally, and your whole spirit will melt into the sequence. This is not unlike performing music. If one musician just plays the music and the other plays it with his whole heart and mind, the two performances are as different as night and day. In one case the music is dead, while in the other it is alive and touches us.
If you don't know how to incorporate jin into the forms, then even if you do the sequence for many years it will still be dead. In order for the sequence to be meaningful, jin and technique must be combined. An important way to do this is to practice fast taijiquan. Practicing fast taijiquan is part of the Yang aspect of taijiquan and it allows you to manifest your internal qi into external forms and power. Once you can do the sequence of movements automatically and can coordinate your breathing and qi circulation with the movements, you should practice doing the form faster and faster. Remember, if you ever get into a fight, things are likely to move pretty fast, so you have to be able to respond fast in order to defend yourself effectively. If you only practice slowly, then when you need to move fast your qi will be broken, your postures unstable, and your yi scattered. If any of this happens, you will not be able to use your jin to fight.
"The Fair Lady Weaves with Shuttle"
(Zuo Yu Nu Chuan Suo) 玉女穿梭*
Therefore, once you have developed your qi circulation you should practice the sequence faster until you can do it at fighting speed. Make sure you don't go too fast too soon, or you will sacrifice the essentials such as yi concentration, qi balance, breath coordination, and the storage of jin in the postures. When doing fast taiji, do not move at a uniform speed. Incorporate the pulsing movement of jin so that you are responding appropriately to the actions of your imaginary enemy. It is difficult to develop the pulsing movement of jin solely by doing the sequence, so you should also do jin training either before or concurrently with the fast taijiquan.
If you are interested in knowing more about taijiquan jin development refer to Tai Chi Theory and Martial Power, published by YMAA.  
Postures and Taijiquan
Since taijiquan is an internal qigong martial style, correct posture is essential. Incorrect postures can cause many problems: a tight posture can stagnate the internal qi circulation, wrong postures may expose your vital points to attack, floating shoulders and elbows will break the jin and reduce the jin storage.
Large and Small Taijiquan Postures
Taijiquan students are generally taught to make the postures large at first. This helps the beginner to relax, makes it easier to see and feel the movements, and also helps him or her to sense the qi flow. Furthermore, because large postures are more expanded and relaxed, the qi flow can be smoother. Large posture taijiquan was emphasized by Yang, Cheng-fu  and has been popularly accepted as the best taijiquan practice for health since 1926.
"Single Whip" part 2 (Dan Bian) 單鞭*
Large postures also make it easier to train jin. It is more difficult to learn jin with small postures because the moves are smaller and quicker, and they require more subtle sensing jins. Large postures build the defensive circle larger and longer than small postures, which allows you more time to sense the enemy's jin and react. It is best to first master the large circles and only then to make the circles smaller and increase your speed.
In addition, when you begin taijiquan, you should first train with low postures and then gradually get higher. When you first start training taijiquan, you will not understand how to build your root by leading your qi to the bubbling well cavity
KI 1: Yong Quan on the soles of your feet. Without this firm foundation, you will tend to float and your jin will be weak. To remedy this problem, you should first train with postures, which will give you a root even without qi and simultaneously develop your qi circulation. Only when you have accomplished grand circulation  and the qi can reach the bubbling well can you use it to build the internal root. This is done by visualizing the qi flowing through your feet and extending into the ground like the roots of a tree.
At this time you may start using higher postures and relaxing your leg muscles. This will facilitate the qi flow, which in turn will help you to relax even more. In the higher levels of taijiquan, muscle usage is reduced to the minimum, and all the muscles are soft and relaxed. When this stage is reached, qi is being used efficiently and is the predominant factor in the jin. Usually it takes more than thirty years of correct training to reach this level. Train according to your level of skill, starting with the larger and lower postures and only move to the smaller and higher postures as your skill increases.
To summarize: build your qi both externally and internally, and circulate it through the entire body. After the internal qi can reach the limbs, use this qi to support your jin. Gradually de-emphasize the use of the muscles, and rely more and more on using the mind to guide the qi. Train the postures from large to small, low to high, and slow to fast. First build the defensive circle large, and then make it smaller. For maximum jin, strengthen the root, develop power in the legs, balance your yi "mind" and qi, exercise control through the waist, and express your will through your hands. It is said in the Zhang, San-feng classic: 
Editor's comments: The above is from How to Practice a Taijiquan Sequence, by Dr. Yang, Jwing-Ming. It was slightly modified to fit the style and format of Qi Encyclopedia.
 ^ Jin is the manifestation of Qi [bio-energy or bio-electricity] into muscular power. See p.73 in Dr. Yang Jwing-Ming. Tai Chi Theory and Martial Power: Advanced Yang Style Tai Chi Chaun YMAA, 1996.
*Photos of Dr. Yang in this article were produced by Paulo Segadaes.
See Dr. Yang, Jwing-Ming for further biographical and publications information.