Relax and extend
The unbendable arm is a concept that is talked about a lot in tai chi and aikido. However, it is a part of most traditional Chinese martial arts. It is a way of holding your arm so that it cannot be bent at the elbow no matter how hard somebody tries. Eventually the same principles can be applied to any joint in the body.
The point of the unbendable arm is to ensure that your physical structure doesn’t collapse when pressure is applied to it.
The best way to test it is to rest the back of your hand on someone’s shoulder then get them to pull your arm downwards while you try to maintain a straight arm. Clearly if you are much stronger than them you can do this easily so find someone at least as strong as you are to test it on. When you resist in the normal way they should still be able to pull your arm down, bending it at the elbow and you fail.
To succeed at the unbendable arm you need to learn to hold your arm a different way. Before your partner starts to push down imagine a force going through your arm and being projected out through your fingers. Some people imagine a jet of water flowing out strongly and bursting through the wall/obstacles in front of them. Others imagine a beam of light projecting far out into the distance. Others find it better to imagine their arm as being 20+ feet long.
Experiment with different visualisations to see what works for you. The key thing is to maintain this mental focus of something going through the arm and increasing it’s apparent length and to stay as relaxed as you can while you do so. When you get this right there is no way your partner, however strong he may be, can bend your arm.
The practical unbendable arm
The unbendable arm is an essential part of developing a powerful shield and is used throughout the tai chi form and many kung fu forms. Any time your arms are extended and slightly bent at the elbow your arm should be unbendable. After a while it becomes second nature to keep them extended so the energy can flow freely and the arm can’t be bent.
In push hands it prevents your opponent from collapsing your arm and enables you to protect yourself, feel what your partner is doing and redirect their energy without tensing up.
In combat it is used in blocks, throws and joint locks. When you block or strike someone with your unbendable arm there is no give at your elbow joint so your arm will feel like an iron bar (at least it will when fully developed). This will make it all but impossible for anyone to grab your arm and apply a joint lock.
So learn it today. It’s one of those skills that is quick and easy to master yet is so useful in so many aspects of tai chi and life.
Stay relaxed or it won’t work
Any tension in your arm will have the effect of putting a block in the way of that flow of intention. It’s like stepping on a hosepipe. Do so and the water just trickles out of the end.
Once you get the hang of it the unbendable arm can be mastered in just a few minutes (contrary to what many tai chi people will have you believe).