- Tokyo (東京) officially Tokyo Metropolis (東京都), one of the 47 prefectures of Japan, has served as the Japanese capital since 1869.
- As of 2018, the Greater Tokyo Area ranked as the most populous metropolitan area in the world.
- Tokyo was formerly named Edo when Shōgun Tokugawa Ieyasu made the city his headquarters in 1603.
- It became the capital after Emperor Meiji moved his seat to the city from Kyoto in 1868; at that time Edo was renamed Tokyo.
- As of October 1, 2015, the population of Tokyo is estimated to be over 13.4 million, or about 11% of Japan's total population.
- Tokyo ranks first in the Global Economic Power Index and third in the Global Cities Index.
- Tokyo has the largest metropolitan economy in the world. According to a study conducted by PricewaterhouseCoopers, the Greater Tokyo Area (Tokyo-Yokohama) of 38 million people had a total GDP of $2 trillion in 2012 (at purchasing power parity), which topped that list.
- Architecture in Tokyo has largely been shaped by Tokyo's history. Twice in recent history has the metropolis been left in ruins: first in the 1923 Great Kantō earthquake and later after extensive firebombing in World War II.
- Tokyo has enacted a measure to cut greenhouse gases. Governor Shintaro Ishihara created Japan's first emissions cap system, aiming to reduce greenhouse gas emission by a total of 25% by 2020 from the 2000 level.