Why it's the capital
Under its old name, Edo, the city became the seat of the Tokugawa shogunate in 1603. In 1868 it was renamed Tokyo, meaning "Eastern Capital", and Emperor Meiji moved the capital here from Kyoto.
Capital of JapanTokyo lies at the head of Tokyo Bay in the Kantō region, on the central coast of Honshu, Japan's largest island.
Under its old name, Edo, the city became the seat of the Tokugawa shogunate in 1603. In 1868 it was renamed Tokyo, meaning "Eastern Capital", and Emperor Meiji moved the capital here from Kyoto.
Picture Japan's long chain of islands and aim at the middle of the biggest one, Honshu, on its Pacific side where Tokyo Bay opens to the ocean.
Kyoto, the imperial capital for more than a thousand years, has the same letters in a different order, but it lies inland in a valley to the west-southwest; Tokyo is the one on Tokyo Bay.
Sources: Wikipedia: Tokyo, Wikipedia: Tokyo Bay, Wikipedia: Ogasawara Islands, Wikipedia: Kyoto