Hi Jacopo!
Thank you for your message.
And welcome to Japan. hope you enjoy your stay :)
As you say, Tokyo is a big city, almost a country.
If you're interested in Japanese calture, you should go Asakusa, Kamakura, or Tsukiji.
If you like high technology, you may go Akihabara, Shibuya, or Harajuku...
There are so many place to see.
I can't write everything :)
But I think you'll have fun and find something new when you just walk the street.
Hey, I saw your photos on your web.
They're so lovely :)
I wanna see your photos of Tokyo.
kahori