This is the fifth part of Marshal Yue, Fei's "Ten Important Theses" an excerpt from Xingyiquan—Theory, Applications Fighting Tactics and Spirit.  This is Thesis No. 9. For Theses 1-8, see Parts 1 through 4.

9. Thesis of Stepping (Bu Fa Lun)

When the five sensing organs and hundred skeleton bones decide to move, in fact, they are transported by the stepping. The stepping is the foundation of the entire body and the governing key to movement. Therefore, engaging in battle and matching the opponent relies on the body, (but) actually the main support of this is nothing but stepping. (Although) the changes, which correspond to the situation and opportunity, are in the hands, however, that which enables the hands to switch and move around is also in the stepping. Advancing, retreating, turning around, and beware of the sides, if not for the stepping, how could (you) catch the opportunity to stimulate (the Qi) and also to raise, extend, and withdraw. If not for the stepping, how could (you) demonstrate the marvelous variations? What is called the tricky keys are in the eyes, the variations are (generated) in the heart. Then it is possible to turn around and change angles, thousand variations and ten thousand derivations, which prevent (you) from being forced into an urgent (situation); if not from the actions of stepping, how could it be done? (However, all of these) goals cannot be reached by force.

It is the stepping, which gives your strategy life and creates the hundreds of variations. It is also the stepping, which allows you to react naturally to an attack and avoid or escape from dangerous situations. It will take a lot of practice and accumulated experience before you are able to reach this goal without forcing it. If you can only achieve these variations by force, then your attention is on the forcing, and your reactions will not be natural and automatic, and your stepping will not be effectively coordinated with your strategy.

The movements originate from no heart (i.e., no intention) and the excitement is generated from no feeling. When the body wishes to move, the stepping will also move around (automatically). When the hands are going to move, (you have) already stepped to the (opponent's) urgent position. This happens (naturally) without expectation, progresses without being pushed. Isn't this what is called the top wishes to move the bottom naturally follows? Furthermore, stepping is divided into front (leg) and rear (leg), the one with definite positions (i.e., the front leg) is stepping, also the one without definite positions (i.e., the rear leg) is also stepping. Such as the front leg steps forward, the rear leg will follow. The front and the rear all have a definite position. (However), if the earlier stepping (leg) steps later, and the later stepping (leg) steps first, also if the earlier stepping (leg) is used as the first stepping (leg) for the later, or the later stepping (leg) is used as the following stepping (leg) for the first, then the earlier and the later stepping (legs) will naturally not have definite positions. In all, when (we) talk about the situation of the fist (i.e., style), the important point should be considered to be stepping. Lively or not is also decided by stepping. Agile or not also depends on stepping. How great are the applications of stepping!

Your strategy is from the heart, but your movements must be from your natural reactions. When a situation arises, everything happens very fast and you have no time to think. If you have not acquired natural, fast, and accurate reactions through your training, you have already lost the battle. In order to acquire this automatic fighting strategy you must train until every single part of your body is involved in every movement you make. Then, every tiny part of your body will be involved in the fighting. This means that when one part of your body moves, no part doesn't move, and if one part is calm, all parts are calm. Only then will your stepping and techniques be natural and effective. When you are at this stage, then there are no set rules.
The fist (i.e., this style) is named Xin-Yi (heart-mind). In Xin-Yi, the Yi (intention) originates from the Xin (heart) and the fists are emitted according to the Yi. (You) must know yourself and the opponent, following the opportunity and responding with variations. (When) the Qi in the heart is emitted, the four limbs all move. (When) the feet are raised, they are grounded. (When) the knees are lifted, they have number (i.e., specific techniques). (When) turning, there are positions. Combine with the shoulders and coordinate with the hips, three tips are matching, and the Xin, Yi, and Qi internal three are (also) combined. The fist is combined with the feet, the elbows are combined with the knees, and the shoulders are combined with the hips, external three are combined. The palm centers, the sole centers, and the Xin, three centers and one Qi are mutually combined. (When it is) far, the hands are not emitted. (When) the fists are used to strike within five feet and beyond three feet, (it does) not matter (whether moving) forward, retreating, moving to the left or to the right, every step corresponds with each fist (strike). The rule is (it is) marvelous if (it) is able to reach the opponent and (he) cannot see your shape.

Xingyiquan is sometimes called Xin Yi Quan, because the heart (emotional mind) plays such an important role. Once the Xin is generated, the Yi takes over to provide clear judgment. Finally, the strategy is decided and the techniques are applied. The Xin and Yi are the masters of the fight, and once a decision has been made, action follows immediately.  That is why it is said that when the Qi in the heart is emitted, the four limbs all move. The entire body moves as a unit, and the feet are always rooted. In addition, the three tips (tips of the nose, hands, and feet) must line up, the three internal combination (Xin, Yi, and Qi) and the three external combination (hands-feet, elbows-knees, and shoulders-hips) must also be established. Furthermore, in order to become a coherent unit in a fight, you must also combine the internal and external.
When you are in the middle range, every time you step you should strike the opponent, and every time you strike the opponent you should step. When you act, do not express your intention in your face or reveal it in your posture. Then your opponent will not be able to figure out what you are going to do.

Deeper Secrets of Fighting

When the hands are emitted, (they are) fast like the wind and the arrow. (When shouting), the sound is like thunder. Appear and disappear like a rabbit. It is like a lively bird entering the woods. Encountering an enemy, (you are) like a giant cannon whose power can destroy a (thick) wall like a thin one. The eyes are sharp and the hands are fast. When you jump forward, it is straightforward for swallowing. Before exchanging hands, the Qi is already forward. Once the hands have entered (i.e., the fight has started), the agile movements are most marvelous. (When you) see an opening, do not strike. (When you) see the Heng, then strike. (When you) see the opening, do not stand firm. (When you) see the Heng, then stand firm. Top, middle, and bottom, hold the Qi steady. The body, feet, and hands are all following orders. They are not raised because of the opening and they do not fall because of the opening. The wisdom and skillful tricks all depend on the aliveness, ability to go, ability to fit in, ability to be soft, and ability to be hard, ability to advance, and ability to retreat, (when) not moving, steady as a mountain, as difficult to figure out as Yin and Yang, unlimited like the heavens and the earth, and full like a huge granary. (Your understanding) is extensive and (knowledge is) abundant as the four seas. (You are) bright and shinning like the three lights. Inspect the opportunity of the opponent's attack and determine the advantages and disadvantages. There are advanced techniques where (you are) calm and wait for the movement. There are borrowing techniques where (you) move to deal with the (opponent's) calmness. The borrowing techniques are easy and the advanced techniques are hard. The advanced techniques should still be considered first.

This section exposes the deeper secrets of fighting. The depth of your fighting experience will determine how much you really comprehend of the profound contents of this paragraph.  The first few sentences state the feeling and the appearance of the actions. The second few sentences discuss strategy. The last few sentences talk about techniques. The best and most advanced technique is to keep yourself very calm and alert, and wait patiently for the opponent's first move. There is a martial arts proverb that says: "When the enemy does not move, I do not move. When the enemy moves slightly, then I move first." If you are interested in more on fighting strategy, please refer to the book, Tai Chi Chuan, Martial Applications, by Dr. Yang.

However, if your opponent remains calm for a long time, you may want to do something to make him move first. Then you have to borrow a technique. This means that you temporarily "borrow" a technique to use it as a fake - it is not your actual attack. The text reminds you that the best technique is to wait until your opponent moves first. If you have to borrow a faking technique, then your attention will be on your offensive strategy and your defense will be weak for a moment. Therefore, borrowing techniques are not as good as waiting techniques.

Those who are exchanging bravery (i.e., fighting) should not think about mistakes (already made). Those who think about the mistakes find it hard to move even an inch step. (The movement) rises like a penetrating arrow and falls like the wind. (When) the hands grasp the hands, attack forward. Every movement automatically combines secretly. Speedy like lighting in the sky and beware of the two sides, left and right. Turning to the rear is just like a tiger searching the mountain. (When) chop and strike are used, (they are) intrepid and undefeatable. Chop the endings (i.e., limbs) and attack the face, aiming for the Zhongtang. (When) thrusting upward and downward, it is like a tiger, also like an eagle swooping downward to a chicken coop. Do not be hurried in turning over the rivers and reversing the ocean. A single phoenix that dares to fly toward the sun can be said to be brave. (When) the clouds are covering the heavens and the moon, the heavens and the earth interact (i.e., there is a storm); when martial arts are competed the winner and the loser can be seen.

While fighting, you should not be thinking about errors you have made. If you are doing this, you are not concentrating on the fight, and so your stepping and use of techniques will be stagnant.

When stepping, an inch apart and step a foot. Chop forward to the face and step the right leg and advance with left steps, following this method to move forward. (When) approaching the opponent (to attack), advance your body. (When) the body and the hands arrive together, then (the techniques) can be real. Within the emitting, how do (we) understand the secret application? When the meaning has been explained, its marvelousness can seem to be supernatural. When a bird of prey enters the woods, it must not catch its wings. (When) an eagle is seizing a small bird, its postures are balanced in four directions. To win the victory, the four extremities must be gathered neatly. First, (you) still need the hand to protect the heart. Plan the strategies and apply them skillfully, a spirit of thunder and a venomous heart is the best policy. (Then) the hands and the eyes are able to defeat the opponent.

When you step forward, avoid a wide stance; keep your feet only an inch or so apart and only step about a foot each time. This way you will always maintain a firm stance and an effective defensive posture. The two legs should take turns advancing. When you advance, the body must also move together with the stepping and occupy the opponent's center door (Zhong Men). When you attack, your stepping, body, and hands must all arrive at the same time in order to be effective ("real"). This is the secret of emitting.

When you attack, you must avoid having your technique interrupted, like a bird flying into the woods and catching its wing on a branch. You must also be calm, firm, and balanced in all directions. In addition to good strategy and good protection, you must also have a sharp and mean look and a raised spirit, and then you will be able to win.

What is dodging? What is advancing? To advance is to dodge and to dodge is to advance. Do not look for the distant answer. What is called a strike? What is called beware? To beware is to strike and to strike is to beware. The hands are just simply emitted. The heart is like gunpowder and the fist is like a cannon ball. When the trigger is moved, it is hard for the bird to fly (away). The body is like a bow and bowstring and the hands are like the arrows. When the string is aimed at the bird, the marvelous results will be seen. When the hands move, like lightning; lightning is so fast that there is not enough time to close the eyes. The striking is like thunder and it is so fast that (you) do not have time to cover your ears. The five paths are actually the five entrances. Nobody protects them but yourself. When the left hand passes the cheek (to block), the right hand will go (to attack). When the right cheek's hand is going, the left cheek's hand is coming. The two hands are bound (into) fists (i.e., held tight) and released to the (opponent's) face. The doors of the five gates are tightly closed. The fists are emitted from the heart and fall onto the (opponent's) nose. The feet are (grown) from underneath the ground. When a foot is raised fast, the heart Fire is flaming. The Five Phases are Metal, Wood, Water, Fire, and Earth. The Fire is flaming upward and the Water is flowing downward. (If) I have (the coordination of) the heart, liver, spleen, lungs, and kidneys, then the Five Phases can mutually cooperate without mistake.

In a fight, a dodge can be used as an advance and an advance can be used as a dodge.  You should not be bothered with trying to distinguish all of these. Simply react naturally and automatically.

It is not clear what the five paths (Wu Dao) are that the document refers to. Since the five paths are considered to be the five gates, which the opponent is able to enter, they may be the face, chest, abdomen, groin, and shin, which are the five common zones for an attack. However, it may imply the five directions, which the enemy may enter, the front, rear, left, right, and center.

The above is an excerpt from Xingyiquan—Theory, Applications, Fighting Tactics and Spirit by Liang, Shou-Yu and Dr. Yang, Jwing-Ming.