Note 6 — Letter from Dasmarinas to the Ruler of Japan

The Japanese calendar was based upon the lunar year; and the years were divided into cycles of sixty years each. Besides this division, there is another and more arbitrary one, into periods between important historical events, which divisions are named from a list of Chinese words specially set aside for this purpose. The name used in this document, Tienchen, is that of one of these historical periods; it is written “Tensho” by Griffis, and its dates given as 1573–92. See Rein's Japan, pp. 434–437; and Griffis's Mikado's Empire, pp. 623–626.