Some useful links when travelling to Japan:

-Tokyo Train map: Train Map
-Japan Train guide (type the stations and you will get directions):
-Japan Train Route finder by Jorudan
-Gym Guide: Japan-MMA Gym Guide Its a while ago I made it, but should still be ok. Might need to make some additions to it though.
-How to get to Differ Ariake/Ariake Colosseum: Getting there: Differ Ariake

Just for inspiration, a picture I took from Haneda Airport:

Great links! I might go to tokyo in april if everything turns out as planned and I'd love to train some MMA while I'm there!

Real estate agency for foreigners in Tokyo in English --- tokyorent.com