In keeping with East Asian tradition we generally place the surname before the given name—for example, Kawakami Hajime. We usually refer to individuals in their youth by given name (Hajime) and then in adulthood by surname ( Kawakami). When the given name changed several times ( Nogi for example, used several different names before settling on Maresuke at the age of twenty-two), we selected the best known. Before the Meiji period, changing one's given name was common and caused substantial confusion even among Japanese. An individual had both an official or "true" name (jitsumyō) that remained unaltered and a common or popular name (tsūshō) that could be changed at different points in life. In addition, educated people, especially writers and artists, often adopted a pen name (gō) that might be changed several times. After a national census registration was established in the Meiji period it became more difficult to change one's given name and the practice declined. Even today, however, some Japanese change their given names after the occurrence of a disaster or its prediction by a fortune-teller. Because the situation differs with each individual in our study, we explain our use of names toward the beginning of each chapter.
In calculating ages throughout the book, we use the Western method, rather than the traditional Japanese method in which the day of birth is counted as one year, the next New Year's Day as two years, and so on.
The lives of the six Japanese men discussed in this book span the Tokugawa era, named for the family of ruling shoguns, and the Meiji, Taishō, and Shōwa historical periods, each named for reigning emperors. The Tokugawa era, from 1600 to 1868, is a time of strict national isolation and semicentralized feudalism. The Meiji period, from 1868 to 1912, is the time of Japan's emergence as a modern power. The Taishō period, from 1912, to 1926, includes important experimentation with democratic froms. The Shōwa period, from 1926 through today, includes Japan's interval of ultranationalism, militarism, and war, as well as the post-Second World War era.