You're mixing up eras and reigns. The "Edo period" refers to the years when the shogunate ruled from Edo (today's Tokyo), during which there were over a dozen

You're mixing up eras and reigns. The "Edo period" refers to the years when the shogunate ruled from Edo (today's Tokyo), during which there were over a dozen (notionally) reigning emperors: https://en.wikipedia.org/wiki/Template:Timeline_of_Japanese_era_names https://en.wikipedia.org/wiki/Template:Timeline_of_Japanese_...