Bevel Gear

by Kelvin Ho on 2022/06/04

Today we did an exercise to rotate the torso horizontally from left to right (first gear), while the arm with the elbow straight as a stick rotated in Ni Chan (second gear).  The second gear’s rotation was driven by the first gear. The result was like how the train wheel turned, and the rod attached to the wheels moved along the rotation without changing direction.

The torso is attached to the arm in the same way as how a bevel gear works as shown in the diagram above. As the torso rotates, the arm must rotate proportionally. This is the result directly related to how it is set up. In action operation, it is key to start the arm rotation from the armpit. Another important part is that the action must be initiated by the kuas, causing the waist (torso) to rotate, in turn, causing the arm to rotate. When the torso must also be like a solid cylinder, when the waist (bottom part) turns, the shoulders/chest (top part) must turn together. This is said to have one action, while two different parts are moving/rotating in their own designated ways. In the future, there can be more than two gear discs attached together, one action drives many different individual movements. In taiji, this is known as when one part moves, all parts move.

The shoulder is where the split happens. It is the middle that is not involved in either side. No power should be added at the shoulder. This allows the dantian and the fist to be connected. The resulting action is called a “through fist/通拳“, it is not a punch in the normal sense.

When observing others performing the same exercise, the following common mistakes are noted:

  1. The torso rotation is limited to above the chest – The arm rotation is only driven by the horizontal chest rotation. The bevel gear is still working in this way, however, it lacks an extra level of indirectness (the vertical distance) created when the kuas initiates the action.
  2. The two gear discs are not attached – The person is independently moving the arm and the torso trying to match the rotations and make them proportionally. The external appearance is almost the same as the intended outcome, but the mechanics are not.
  3. There are no two gear discs at all – When the person rotates the torso, the arm will change the direction that it is pointing at following the torso rotation.
  4. The torso is not one solid cylinder – When the person attempts to rotate from the kuas, the chest adds a separate action and does not follow the action from the kuas. The result is that there is a twist in the torso, the energy leaks at the left shoulder.
  5. The arm is pushed by the shoulder – The person uses power at the shoulder to push the arm out. The torso rotation is not involved, i.e. no bevel gear setup.
  6. Using the arm to punch – The person is using the upper arm to throw a punch.

In taiji, the concept of a bevel gear is very important in understanding how we should connect our various body parts.

The full instructional video can be found at

About Kelvin Ho

Kelvin Ho, Master Chen Zhonghua's disciple, is the instructor for Practical Method Toronto. He has been teaching and promoting the Practical Method system in Toronto, Markham, Richmond Hill, Canada since 2011. He has received numerous medals in various Taiji competitions. He is also a vice-president of MartialArts Association Canada. Like his teacher, he feels an obligation to pass this great art onto others. Contact:

{ 2 comments… read them below or add one }

James Chan June 5, 2022 at 1:19 pm

Good illustration of an advanced and multi-dimensional concept. Another gear to illustrate Master Chen’s teaching is the dual racks and pinion. This is a linear concept and has been explained and demonstrated by Master Chen in many of his earlier workshops. While the pic below to illustrate dual racks and pinion seems simple, it is not simple to apply but with time and proper teaching one should be able to see results. Other concepts and abilities require to make this work include but not limited to the following (this is based on my own training and understanding and most likely is an incomplete list):
• Finding (or creating) the pipe, the lines, the dots and the pivot.
• I use the term pipe to illustrate direction, there may be multiple lines inside a pipe that need to be collapsed into a single line within the pipe.
• There may be multiple pipes in different directions at the beginning. They will need to be re-aligned into a single pipe in the same direction.
• Do not move the pipe, the line, the dots and the pivot.
• Understand and able to apply realignment through extension in opposite directions at the pivot point.
• Re-alignment may require multiple instances and each instance may have a different pivot point.
• For energy to go outward apply energy inward (this is in terms of the direction of the energy).
• For energy to go outward the inner rings must be stronger than the outer rings. (This concept is explained in Master’s Chen video and not repeated here)

I experimented the dual racks and pinion with Dina Kerr a bit in the last Maple Ridge workshop and am beginning to feel at ease to apply this in my positive and negative circles. The result is amazing. It is like an indirect push by applying energy inward.

In my opinion, the obvious places to start working on dual racks and pinion are the arms and the legs. When you are able find them and apply them with ease, you can now try to find this in your dantian. Once you are able to find this in your dantien, you can now try to connect all of them through your dantien. If you are able to connect and not stuck, it is a sign that you are able to do some level of 轉關 (re-positioning) and 開胯 (beginning to be able to use the kua to re-position).

Link to the pic foe dual racks and pinion.


James Chan June 5, 2022 at 8:17 pm

One of the translations of 後發先至 is a strike deliver later hits first. This translation is in terms of timing and is not applicable in Practical Method (I say Practical Method because I have never heard this concept explained in other Taiji). In Practical Method, according to Master Chen, 後發先至 refers to direction. The dual tracks and pinion could help to explain this concept. The energy send backward results in energy send forward instantaneously.


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