Temple of heaven - Tai-chi session, unarmed

Tai chi is a Chinese Taoist martial art : it was and is still practiced by monks.
As its movements help strengthen the body, it is very popular among seniors who practice it in the morning in the parks. The qigong, whose goal is the circulation of chi (energy, vitality), looks very similar to tai chi and it requires a lot of knowledge to be able to differentiate them...