Popularized by the Ultimate Fighting Championships, Pride, and other physical contests, submission grappling - in which fighters use locks, chokes, and breaking techniques to defeat their challengers in no-holds-barred matches - is unique in modern Chinese martial arts in that it retains the grappling aspect of combat. The seminal work in the field is 'Submission Grappling'. First published in 1936, the book explains a wide range of movements from press and blows on vulnerable points to grappling, strangling and throws. 'Impacts on the enemy' moves allow the fighter to separate muscles and sinews (feng jing); dislocate bones and joints (yu gu); and impact on points (dian xue). The book shows how to use these methods skillfully, not just with brute force. 'Chi na fa' is a comprehensive explanation of these techniques, from which derive many currently popular techniques such as jiu-jitsu.