In the Cheng Man Ching school of Tai Chi Chuan the Nei Gong, or internal power excercises, are only taught to those who have made the commitment to become a disciple of their teacher. The system of internal power exercises the disciples learn are derived from the Zuo Lai Feng Daoist practices studied by Professor Cheng Man-Ching. These consist of a specific breathing technique and internal visualisations, coupled with precise physical postures and movememnt.
In Chinese martial arts traditions, there has always been some form of body conditioning. In some cases this is by striking but there is a tradition of Qi Gong practice to make the body impervious to blows. If you watch the Chinese New Year celebrations, you will often find demonstrations of this, with people bending spears on their throats, breaking iron bars on their heads, taking blows to the soft parts of their body, or washing their arms and faces with broken glass.
There is no way this type of Qi Gong can be learnt other than direct from a teacher as the exercises can be dangerous if done incorrectly.
Zuo Lai Feng
A previously unheard style of Tai Chi, the Zuo style is inherently a Taoist art. Although many people deny its existence, particularly some of Cheng Man Ching's disciples, it was referred to in Cheng's writings, yet he chose not to pass on much of this art to his students, with the exception of Master Wu Kuo Chung. What is known of its origin has been orally passed down according to the following story.
Many years ago in Guandong province in China, there was a famous martial artist called Zuo Lai Feng, or Tso Lai Peng, nicknamed Guandong Zuo Yi Dao, or Single Sabre Strike Zuo of Guandong. His sabre was over 81 catties in weight (about 40 Kgs). One day when he was putting on a great display, he heard someone laughing among the usual applause. It was a middle-aged Taoist priest who questioned whether Zuo could possibly kill anyone with such a heavy sabre. After further taunting he persuaded Zuo to attack him and to Zuo's astonishment the priest avoided the sabre and with one hand disarmed Zuo. As this nameless priest walked off, Zuo left to follow him, his students looking on speechless. For three months Zuo followed the priest until eventually he consented to teach Zuo these secret Taoist techniques of internal gong fu.
Time passed and the priest eventually disappeared. As the story goes, Zuo Lai Feng later returned and taught his new form of internal martial arts. Another famous martial artist was Zhang Qin Lin, or Chang Chin Lin, who also studied Tai Chi from the Yang family, mostly from Yang Cheng Fu. His notoriety spread as a martial arts champion until he caught the attention of Zuo Lai Feng, who sent one of his students to challenge Zhang. Although Zhang was initially reluctant to accept the challenge, he eventually accepted. He was defeated by this student and it was enough to persuade him to become one of Zuo's disciples.
Zhang Qin Lin was several years senior to Cheng Man Ching. As both were students of Yang Cheng Fu, their relationship developed. At the time, Zhang was still illiterate and one day Zhang agreed to teach Cheng Man Ching the secrets of the Zuo style in exchange for educating him to read and write. In this way Cheng Man Ching was later to adapt his Tai Chi to conform to many of the principles learnt from the Zuo style