Great point! here However I desagree- Tai chi is Yin and Yang in operation but to real train at it we must sink tottaly in an Yin state (relaxation) with a strong core (yang) . How one can achieve this? Only with intensive practice under a real teacher, what is very rare nowadays! The question is that today nobody is willing to " invest in loss" (yes tofu state) and from there attending a kind of steel inner power.