Tan-sau, or “Palm-Up arm” (also called “Dispersing-arm” in some lineages), is one of those movements that creates a lot of controversy among the families.
Some will train Tan-sau with the hand in-line with the forearm while others train it with the back of the hand parallel to the floor. So let’s see some of the differences and why so many are adamant about their chosen positions.
Tan-sau is an action that allows for defense against straightline attacks. Because of the elbow position with the palm facing upward, the structure of the arm is such that it is not very strong against hooking punches. That is just the nature of physics when it comes to this particular position.
With the palm facing downward like in Fook-sau, the forearm rotates the opposite way, and this position allows for greater structure (natural strength), which in turn allows for competent defense against hooks or more angular attacks. But with the palm upward, this type of structure is removed; ergo, Tan-sau is best used for defense against straightline punches.
Next we have the hand angle itself. A simple test will show this “natural strength” I mentioned.
If you bring your Tan-sau hand forward, first put the hand in-line with the forearm so that there is a straight line from the elbow to the fingertips. Now have your training partner press on your forearm so that they are pushing the arm towards your chest.
In most cases, Tan-sau will have a tendency to collapse a bit unless you are extremely strong. That is just the physics of force-to-force in this position. The pressing force is generally more than than the defending force can sustain.
Now, flatten the hand so that the palm is facing upwards and have your training partner repeat the press on your forearm. In this position, you will find that your arm can actually withstand more of this force without collapsing. Why? Because the structure (natural strength) of the arm and shoulder has been increased, thereby allowing you to provide a stronger press to the opponent’s press.
Further still, and keeping the palm flat, angle the hand slightly outward now so that the fingers are pointed a bit to the outside. With your partner repeating this press, now what do you see? An even stronger defense in Tan-sau.
In this position with the hand angled slightly to the outside, there is a bit of contraction in the forearm, which in turn provides more structure.
From all of this, we can see that while many practitioners might think that Tan-sau is an easy movement to defeat, it is actually quite competent when the correct position is assumed. If the palm is in-line with the forearm, Tan-sau can easily collapse with a very powerful attack. But with the palm flat and pointed upwards, Tan-sau becomes a formidable defense.
In your classes, play with the various hand positions to learn what Tan-sau is really all about, and then apply that same concept to other actions in order to experiment. Although the hand positions will vary depending on what you are training, it is essential to experiment with changing positions in order to learn how the body can provide a solid base of movement solely from where your “connection” is at in relation to the incoming attack.
And the more you experiment, the more you learn.
