Tokyo was originally known as Edo (江戸), which means estuary. Its name was changed to Tokyo (東京 Tōkyō, 東 tō east, and 京 kyō capital) when it became the imperial capital with the arrival of Emperor Meiji in 1868, in line with the East Asian tradition of including the word capital (京) in the name of the capital city (like Kyoto-京都, Peking-北京 and Nanking-南京) .