I'm in Tokyo for the the 23rd, 24th and 28th of this month. I would really like to visit a place with excellent sushi. However, I've done little restaurant planning in advance and it's the holidays, so everything is booked (I think the hotel called about 8 or 9 places for me). Does anyone have any suggestions on places where we can just walk in (even if we have to wait) and get great sushi? Both lunch and dinner are possibilities.