The origin of Tai Ji Quan is still a bit unclear but can say for sure that the art was practised in Wen Xian area in the province of Honan where it was practiced in Chen family willage, the Town of Zhaobao and other villages in the area in the 17th century.
Wu Yu Xiang researched the art of Tai ji Quan deeply and travelled to Wen Xian area in order to receive more knowledge of the art. Eventually he became a disciple of Chen Qing Ping and completed his training under him. He also got hold of some ancient manuscripts on the theory of Tai Ji Quan and researching these was able to reorganise what he have learned from his teachers into a new form later called Wu style Tai Ji Quan. Later, Hao Wei Zhen learned the art from Wu Yu Xiang's nephew Li Yi Yu and taught it to Sun Lu Tang. When poeple asked Sun Lu Tang about the form he taugh he said it was Kai He Tai Ji Quan i.e. "open, close" Tai Ji Quan. Later people started to refer to it as Sun style Tai Ji Quan and this is the name used today.
Sun Lu Tang had started his martial arts training with Shaolin Quan in his youth but eventually became a disciple of Li Kui Yuan who was a master of Xing Yi Quan (Form-Mind Boxing). After several years of practice under Li he was introduced by him to Li's teacher Guo Yun Shen who took Sun as a disciple teaching him the finer aspects of Xing Yi. After completing his training with Guo he was introduced by Guo to his friend and Ba Gua Quan master Cheng Ting Hua. Sun Lu Tang lived and studied with Cheng for three years and was then left to practice and research what he had learned on his own.
One day he heard of a martial artist who had come to Beijing but became very ill and lived at an inn nearby. Sun went there and invited the man to come and live in his home while recovering and saved no expenses buying medicine for him. After his recovery the man wanted to give Sun something back in order to repay his kindness but Sun politely refused saying that all martial artist are like brothers and would expect no repayment from whatever favours done. The man, who was Hao Wei Zhen, was impressed by Sun's attitude and good heart and offered to teach him his art of Tai Ji Quan. Sun who had long been interested in this art as it was supposed to be related to the ones he was practising, gladly accepted his offer and thus came to study the Wu style of Tai Ji Quan.
Sun Lu Tang wrote five books on martial arts: "A study of Xing Yi Boxing", "A study of Ba Gua boxing", "A study of Tai Ji Boxing", "A study of Ba Gua sword" and "The true meaning of boxing". These books was among the first on internal boxing to spread widely and are still regarded as classics on the arts. Especially his last published book, "The true meaning of boxing", is regarded as a real treasure on internal martial arts and has affected almost every other branch of martial arts practised today.
Sun Lu Tang chose his daughter Sun Jian Yun to be his successor. Sun Jian Yun did very much to make Tai Ji Quan more spread. She taught several thousand students during her life and had more than 100 disciples, several of them foreigners from such diverse places as Japan, USA, England and Sweden. Sun Jian Yun passed away in the autumn 2003 at the age of 89.
There are three important aspect of Tai Ji Quan that should be emphasised in practice. These three are: 1) The health aspect, 2) The martial/self defence aspect and 3) The Philosophical aspect. You can consider these three aspects as the legs of a three-pin chair. If you take one leg away the chair would fall over. Only when you have all three can the chair serve it true function, without one or two it can only serve as an interesting object to look at (at most).
Remember the important points in practice and always check yourself to see if your movements follows these principles. Practice regularly: It is better to practice for 15 min every day than to practice for two hours once a week. Don't practice on a full or too empty stomach. Find a nice, quiet area for practice (usually areas are nice and quiet in the morning which is the reason why most Chinese get up at 5 a.m. for their daily practice (there are other reasons as well, but out of scope of this article)).
Though TJQ is a really wonderful thing it is also one of the most difficult things to study. In order to make progress in the art it requires more than just doing the form a couple of times every day. It requires research:
The way to research the health aspect of TJQ is basically to develop your feeling of your body-mind (i.e. become aware of thoughts and feelings coming to you while practising and also of the changes in your body when executing the postures). After some years of practice with a knowledgable teacher you should be able to feel when a movement is harmful and be able to correct it.
The way to research the martial/self defence aspect is to think about and figure out different ways to use the movements in the form in a self defence situation. Remember the Chinese saying "although when practising there is no-one in front of your eyes but in your mind there is, although when defending yourself there is someone in front of your eyes but in your mind there isn't".
The way to research the philosophical aspect of TJQ is to study literature on Tai Ji (e.g. the writings of Wu Yu Xiang, Li Yi Yu and Sun Lu Tang and compare the ideas you've found with how the form works.
Let your practice (and life) be guided by the balance principle (not to little and not too much), always seek to find a balance with yourself and your surrounding and you've taken an important step on the Tai Ji way...