Lie (挒), Attach and Turn, is the final of the eight tai-chi methods or use of power. This is the one method with most diverse interpretations. As with my handling of the other methods, here I discuss this method in the light of its relevancy to actual combat situation. What is "attach and turn"? Would it be similar with Cai (採) where a throw is executed by joint locking and body turning?
In tai-chi's Big Luo (大捋) form, an example of using Lie is practiced. There Lie(挒) is used as a defense against Kao (靠). Here we can see the gist of Luo is: In close encounter, attach one's hand to the opponent's attacking point (shoulder as in Kao), turn AND use the reaction force to move away from danger, and (hopefully) throw your opponent to the ground (by using/redirecting his attacking force)! In some cases, it can mean using the throwing power of your opponent to throw him off AFTER one is being thrown. Unfortunately execution of such techniques requires a big difference in proficiency between the opponents. That's why we see it more in demonstration rather than in open competitive sports!
Final question: How chi is used? Answer: the point of chi-contact is the power point of the opponent and it is to be pivoted against one foot firmly rooted on the ground.
This ends my analysis of the eight tai-chi uses of power for tai-chi enthusiasts.