Twelfth generation [[Li Helin]]’s ‘Dashou ge’ ([[Song of sparring]]) applies soft style movement principles to self-defense techniques, with such familiar concepts as: following, sticking, neutralizing, emptying, yielding, and four ounces deflecting a thousand pounds. [[Li Helin]] is also credited with authoring the ‘Taijiquan lun’, ([[Treatise on taijiquan]]), which elaborates the self-defense principles of interpreting energy, sinking the qi, emptying, sensitivity, and avoidance of double-weightedness.Douglas Wile, "Fighting Words" pg. 25