Is tai chi the best martial art for self-defense?

In the short term -- less than a year or two -- external martial arts give a more reliable minimum level of self-defense competence than tai chi. Long term -- with a time horizon of ten years and more -- the balance shifts to a more internal direction. This can be seen in many Japanese and Korean martial arts where at the higher black belt levels, circular, soft, and internal techniques are often considered the choicest meats of advanced training. For more on tai chi as a martial art, see The Power of Internal Martial Arts or The Big Book of Tai Chiⁱ.