Advanced Mechanics Booklet #2 The second in the series of San Szu "Advanced Mechanics and Internal Power Application" texts is now complete. Though the title may seem intimidating for the beginner and intermediate level martial artist, the issues covered are essential for all serious practitioners of Chinese Martial Arts and the Internal Arts or "Nei Jia" in particular. Deals with Internal development in the three main "Nei Jia" as well as internal development in styles typified as "External."