War is largely associated with the loss of texts, yet in many instances it also leads to their emergence. Motivated by the disastrous Japanese and Manchu invasions in the 16th and 17th centuries, the Korean court strived to enhance the Royal Army through a series of reforms and innovations. These efforts included the compilation and publication of a military manual entitled Pyŏnghak chinam (The Compass of Military Learning). A recently discovered version of this book, employing two languages and three different writing systems, provides rare insights into military education, literacy and written culture in traditional Korea.