The term 'Tokyo, Long Ago' refers to the city of Tokyo before it was renamed in 1868. The city was formerly known as EDO, which is a three-letter word that is commonly used to refer to the city during its pre-renaming period. EDO was the seat of power for the Tokugawa shogunate, which ruled Japan from 1603 to 1868. During this period, EDO grew to become one of the largest cities in the world, with a population of over one million people.