A must if youre visiting Tokyo (or other cities as well)

This is the best app I found for figuring out the Tokyo Metro. Make sure you buy the full version as the Lite version requires an internet connection. Very easy to use and it cobers a huge area. They also offer other cities, like Osaka, but also Paris, etc. Dont leave homewithout it!

GuyRoot about Tokyo Rail Map+ Yokohama, Saitama, Chiba, v3.1