Japanese names are written in conventional order with surname first, except in English-language publications by Japanese authors where this order has been reversed. The names of individuals known by multiple names and titles appear here under the name most commonly encountered in the scholarly literature. All Japanese terms are in italics, aside from those that have entered the English lexicon like tsunami or shogun. Macrons are employed for Japanese names and terms to indicate long vowels except when that name or term has become anglicized, such as Tokyo, not Tōkyō, or Kyushu, not Kyūshū. In some instances, descriptions are provided for Japanese terms and book titles in lieu cumbersome English-language translations.
A lunisolar calendar was used in Japan until the formal adoption of the Gregorian calendar on 1 January 1873. For consistency and ease of reading, all dates have been converted to the Common Era (CE) calendar. Dates in the original calendar are included in footnotes when further clarity may be of help. The following periodization serves as a general reference throughout the text: ancient (710–1185), medieval (1185–1467), Sengoku or Warring States (1467–1603), Tokugawa (1603–1868), and modern (1868–present). Premodern refers broadly to before 1868 and preindustrial to before Japan’s rapid industrialization from the early twentieth century.
Until the widespread adoption of the metric system in Japan from the early twentieth century, most measures and weights were recorded in the older system of measurements. All measurements have been converted to their metric equivalent, but the original values and units are occasionally included to emphasize how they appeared in the original documents. The conversions employed for the most common measures mentioned in this book are as follows:
Linear: shaku = 30.3 cm with 6 shaku equaling 1 ken (unit for measuring distances) and 10 shaku equaling 1 jō (unit generally used for measuring the length of things); for measuring longer distances, the primary unit was ri = 3.9 km
Area: 1 chō = roughly 1 ha (10,000 sq m)
Volume: 1 koku = 180 l (slightly more than five US bushels)
Weight: 1 hyō (sack) varied depending on its contents, but 1 hyō of rice generally weighs about 64 kg