Ryochi Zusetsu (2 volumes)

This is technical book on surveying written by Hironaga Kai of the Hitachi Kasama domain, a disciple of Hasegawa of the Seki school. This book was published before the arrival of Commedore Perry and many Western surveying tools were accurately engineered based on a mathematical theory. Wazan scholars began to research the theory and usage of these tools, thus arriving with the publication of numberous technical books on surveying as this book. This book explained in detail the basic choken method which utilized the existing surveying tools made of wood. It also advised readers in the advertisements at the end of the book to only use the sophisticated Western octants after studying the funamentals.