There is a lot of discussion as to whether people can use their Tai Chi as a Martial Art.
When John Kells was teaching a class at the Centre in London, a student remarked that the posture " Deflect downwards, intercept and punch " was the first martial movement they had seen.
What this student, and many others, missed is right at the start, when we need to relax. If you can't relax then you will not be able do much other than exhibit fear and tension.
So " Relax " is the first martial principle.