A newly translated 19th-century book, written by samurai, describes martial arts techniques designed to help police officers of the time. The highly guarded practices included how to tie suspects up using paper string and fighting techniques that allowed officers to defeat suspects without killing them. The book, which contains illustrated instructions, was published in 1888, a time when the samurai class had lost many of its privileges and the formally secretive martial art schools that taught the samurai were willing to divulge their secrets.
http://www.livescience.com/53582-samurai-martial-arts-manual-for-cops-revealed.html
