The Year Names of China and Japan

Japan adopted the practice of using year names of "Nengoh" during 645 A D (the first year of Taikwa). Since then the accession of a new emperor, with the exception of a few, has been marked with a new year title, exactly as has been the custom in China. During the reign of some of the emperors, as many as six new titles have been adopted. Ambiguities have often occurred in computation of time, due to frequent changes of year titles. Changes may take place at any time of the year, and from the ti