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