Tai Chi is about moving in an optimally balanced way. For example, when an arm reaches far, the stance should be long to support it, or else the other arm should reach the opposite way to stay balanced.
The focus is on using soft moves to gracefully deflect hard moves.
In traditional Tai Chi styles, there's a popular exercise called Pushing Hands which is roughly the same as Sticking Hands.
See Master Yan Long Jiang demonstrating some Tai Chi moves.
I've been training with Yan Long Jiang for some months now. Consider joining his classes in Birmingham City Centre.
Visit Yan Long Jiang's website: www.wutaiji.co.uk
Tai Chi refers to great outgoing force (tai) and perfect inward peace (chi). In this way, Tai Chi represents levels 1 & 0 from the ancient levels of fighting.