This list is comprised of Japanese Emperors and Empresses (天皇 Tenno). The first emperor, Jimmu, and his successors are widely considered to be legendary. It is not until the 6th-century that names and dates can be assigned with more certainty. For much of their history the emperors have only been ceremonial rulers, with actual power in the hands of others (such as the shoguns who ruled from 1192 to 1867).
The name listed is the personal name, if known. Deceased emperors are in fact usually referred to by a posthumous name. Since the time of emperor Meiji, this posthumous name coincides with the name of the era.