About “Kōyō Gunkan”
The Kōyō Gunkan is a military record of the Takeda family, compiled largely by the vassal Kōsaka Danjō Masanobu and completed in 1616 by Obata Kagenori. It offers detailed descriptions and statistics of warfare during the Sengoku period. The text is one of the most comprehensive sources on military practices from that time. It also contains the first known use of the term Bushidō. (Summary adapted from Wikipedia, CC BY-SA 4.0.)