Dr Paul Lam
Qi (the life energy) is the driving force of the internal power (Jin). The mind (yi) directs the Qi, and the Qi drives the Jin, in practise, Yi, Jin and Qi are inseparable. In Ancient China, the conscious mind and the sub-conscious mind were not well defined. In fact, the sub-conscious mind is not an accepted concept although it is often expressed as the spirit (shen). Yi in this context can be used to cover both conscious and sub-conscious mind.
Yi (the mind) and Quan (the fist or martial art)