In reply to the question "What is Tai Chi" I use and recommend: "A Martial Art Discipline" . and leave it at that. Folk may not always understand that answer, in this instance that is not important. What is - is that YOU know what it is. To elaborate further is to risk a meaningless stream of words that is just about enough to satisfy the inquirer that Tai Chi is what they always thought it was - a load of wishy-washy mumbo-jumbo that is anything that you want it to be!

The reply "A Martial Art Discipline" conclusively answers the question, so leave it at that and defer more complex or personal qualifications until such time as you have accumulated sufficient PERSONAL EXPERIENCE to base that view upon.

Self-Defence
Fewer and fewer folk (Instructors and Students) appreciate that Tai Chi is a Martial Art - that is to say that 'intrinsic to its development was the need to protect and persevere the body'. Furthermore, this 'way' must be appropriate to everyday life and, in accordance with the other (spiritual) imperative, cause no harm, be not provocative and ideally - not be known by/to an aggressor.

Taichido has been going long enough (and looks professional enough!) to be regarded as some as some sort of authority on Tai Chi. It is not this - but what it is - is an authority on what it does ... and what it does is promote "Tai Chi - with Nothing Added and Nothing Taken Away"; and all that I ask of any student of taichido ("the way of Tai Chi") is only that they "find some space and be themselves".

This, at first, is indeed appear as wishy-washy advice as the other platitudes that confuse the average inquirer that asks "what is Tai Chi". However, I do not address you now as a casual 'inquiry'; I address you as a Budoka - a student or teacher of this 'martial art discipline' called Tai Chi.
By now you should know what I think that is. If my my conclusion: "it is a martial art discipline" is not sufficient then you must content yourself with my only alternative reply which is: Tai Chi is Tai Chi.

As a Budoka that has bothered to find this site, this article, these words I ask you "Where are you, what are you doing, how are you doing it and most important of all: who is doing it or (as in the 'ultimate' Zen Koan "Who am I?" If you merely begin to address these questions to yourself the way of Tai Chi will open before you so wide that there will be "no way" other than "the way it is". Again, this is not as wishy-washy as it sound because a Budoka would understand that as wisdom increases so to does the imperative of discipline (the Mind).
Buddha teaches the Middle Way