Useful info
How to move in Tokyo
The railway network covers the entire city. Trains here are very punctual trains. Train is the easiest option for getting around Tokyo. However there are also some difficulties.
Maybe the biggest problem is at time to buy tickets . Although the signs of the stations are written in Japanese and romaji (literally Roman letters) generally maps are only in Japanese. So buy a ticket, even knowing exactly where to go, can be a real nightmare.
To avoid problems the best is asking the workers of the station, although most do not speak English, help delighted.
Also there are some shared way stations, so before getting on a train, just look at the color!
If you still are not sure you can always ask. Although many Japanese do not speak English they will do what they can to make themselves understood.
Japan Railpass
If you are thinking to travel around Japan for a time and you have temporary visitor status (90 days maximum) then you should think about buying the Japan Rail Pass an option that costs an important amount of money but you will pay off soon.