Marq, the direction going to Roppongi is NOT the direction that initiates at Tochomae, it starts out in the hinterlands. That doesn't mean I don't ride the line, it's by far the best way to get to Roppongi or Azabu Juban from the Park Hyatt, my regular hotel.

mjm, I did the computation and the Roppongi station isn't just 10 floors underground, it's actually more like 13-15 floors underground in the direction coming from Shinjuku! Bring your copy of Jules Vernes' "Journey to the Center of the Earth." The other direction is above at Roppongi, so it's a little better.