Yeah, but it's a city right?From an international perspective Tokyo is a city. Tokyo often calls itself a metropolitan in English — so in a way Tokyo admits it's a city.
However, don't be surprised if locals argue that it's not a city — because politically it's not.
Greater Tokyo AreaIn Japan, there's no concept of a greater city area. However, from a physical perspective Tokyo, Chiba, Saitama, Kawasaki and Yokohama are one giant city.
North American cities often report population based on greater metropolitan areas. For example Toronto reports its population as 5.5 million. Tokyo reports its population as 13.2 million. So it would be easy to think Toronto is almost half as big as Tokyo.
If Tokyo included its greater area its number jumps to 35.7 million — 6.5 times the size of Toronto.
The Cities of TokyoTokyo is divided into 23 "special wards" (tokubetsu-ku). These are generally referred to as cities in English.
These are much like real cities. Residents vote for city councillors. You pay taxes to the city (i.e. taxes are different depending on where you live in Tokyo). You can only get a library card in your home city.
Cities vs NeighborhoodsFrom here it gets a little complex.
People think of neighborhoods in Tokyo in terms of train stations. This can lead to a bit of confusion when there's a city (区, ku) with the same name as a neighborhood.
For example, Shibuya is a neighborhood but it's also a city.
Harajuku is a neighborhood that's in Shibuya city not in Shibuya (the neighborhood). This leads to plenty of mix ups.
It Gets WorseMeguro is a neighborhood that's located in Shinagawa city. There's also a city called Meguro. Meguro the neighborhood is right beside Meguro the city but not technically inside it. You can see how this gets complicated.
Districts vs NeighborhoodsAddresses in Japan are blocks of confusion.
There's another level of complexity to the puzzle of Tokyo neighborhood names. Each city is broken up into districts known as chome (丁目). Chome often have the same name as a city or station.
There is Shinjuku city, Shinjuku station and Shinjuku district (chome). People use all three to identify "neighborhoods" but they're all different things.
Avoiding MisunderstandingsThe political divisions of Tokyo are of great interest to residents and of no interest to visitors. Unless you're eligible to pay taxes or get a library card — who cares.
From a traveller's perspective the best way to identify neighborhoods is by train stations (areas around stations). That's how Japan Talk identifies Tokyo neighborhoods. It's important to be aware that the locals sometimes identify neighborhoods by city (区, ku) or district (丁目, chome).