What I like about Tai Chi Chuan (Taijiquan) is that even when we practice different forms and squabble over how to do them correctly, the underlying principles are the same for everyone. The 10 Tai Chi principles are the very basic principles. And they are the same for EVERYONE practicing Yang style Tai Chi.
These Yang style Tai Chi principles where transmitted orally from Yang Chengfu (楊澄甫; 1883-1936) to his student Chen Weiming (陈微明; 1881-1958). And luckily, Chen Weiming wrote down the principles and they where then published in the book “T’ai-chi ch’üan shu” (The art of T’ai-chi ch’üan; 太 極 拳 術) in 1925.
One of the most-known forms is probably the Yang style Tai Chi 108 form. And to make it confusing for us pracitioners, it has many names: Tai Chi 108 form, 105 form, 103 form, 85 form, 150 form 94 form, 88 form or just: Tai Chi long form.
The number actually depends on how you count the different moves. My current teacher counts the Yin-Yang-phases and says that there are 169 phases! So I guess one could call the long Yang form the 169 form, if he wanted to. Or if you count repeated movemens just once (e.g. “repulse monkey”), you end up with a lower movement count.
I’ve already written a list with the best Qi Gong books. However, I want to be more specific and tell you what I think are the best Qi Gong books for beginners.