Cassius Clay, as he then was , used the yin tactic of avoidance to defeat larger, stronger opponents. He had the ability to read the opponents attacks and use body evasion techniques to evade and ride the attacks countering while the opponent was floundering.
In his first World Title fight against the awesome Sonny Liston, who was highly favoured by the experts to win easily, he so demoralised the reigning champion that the latter threw in the towel after six rounds.
"Keeping his hands low and using his speed and a fast sway to keep out of danger's way, Clay never seemed to be in trouble. Too fast and making Liston look positively pedestrian. By the fourth round, Clay seemed to be able to land crunching blows down on Liston at will."
This demonstrates that although the principle is enshrined in Taijiquan it can be successfully applied in any fighting art.
In his second incarnation, Muhammad Ali, he used the yin tactic of absorption of force against the fearsome George Foreman. This strategy is far more dangerous as it relies upon the body's ability to absorb blows and the hands and arms to ward of attacks to the head. His technique , the Rope-a-dope, was unheard of before then, and I watched the terible onslaught that George Foreman rained upon Ali with dread and fear for his safety. I could not see him surviving that, yet somehow he did. Ali chose his moment perfectly when Foreman's strength was spent to go on the offensive and take him out with his very first counterattack. This was the ultimate example of the interchange of Yin and Yang.
'The Rumble in the Jungle' is one of the most famous fights in boxing - the massive and brutal new champion, George Foreman - against the underdog old timer, Ali, in Kinshasa, Zaire on October 30th 1974. Ali took heavy punishment for 7 rounds but ended the fight in the 8th to become World Champion for the third time
Ultimately we must look at the true victor of that encounter. Ali may have won that fight but at what price?
One of the goals of Taijiquan is longevity in terms of maintaining one's physical and intellectual capabilities in old age. Thirty years on the evidence speaks for itself.