I'm not even sure why I'm bothering to respond at this point; I guess I just happen to be a nice person who's inclined to help by nature. I've been to Nanachome. It was among the most expensive and least rewarding meals I've experienced anywhere. If you're asking because it's the one place you could actually get a reservation at this point, there's likely good reason for that. Was the tempura good? Undoubtedly, it was the best I've ever had. That said, it was just tempura. His prices are beyond exorbitant. Is it worth spending $500-600 a head for tempura? I don't regret visiting myself but I would never return or recommend it to anyone else. It was also the only restaurant in Tokyo with an empty dining room, not surprisingly. My wife and I were literally the only patrons in the entire restaurant, which made for a somewhat awkward and uncomfortable meal. I was also quite disappointed in the repetitiveness of ingredients and lack of diversity or shall I say, stinginess, with respect to the premium ingredients that were served. It felt like an incredibly poor value. For reference, I took my wife to Atelier Crenn for her birthday last week, where we enjoyed a truly memorable dinner at $300/head plus $300 reserve wine pairing, bringing the total to approx. what we'd spent at Nonochome. If I could, I'd return to Crenn every other week, as our entire meal was divine and while nobody would argue it isn't expensive, I found it an excellent value comparatively. We left Nanachome feeling like we'd spent way too much money unnecessarily and would have been more satisfied with $5 tempura from a depachika stall; not that the quality is in any way comparative, but value-wise, we'd have left far more content. Nanachome charges more than Saito, Ryugin and just about every other top kitchen in Tokyo which offer far more ambitious, creative and polished dining experiences. I'd be surprised if he gets any repeat or local business at all. I would probably try Kondo (far more reasonably priced, nicer dining room, more interesting/exotic ingredients, and arguably equal or better depending who you ask) on a future trip, just to see how it measures up. I doubt you'll have any chance of securing a reservation this late in the game and I'm honestly not sure why someone who's never been to Japan would wait until a week before the trip to haphazardly plan a dining itinerary (in one of the busiest restaurant cities in the world, no less) with little to no research, and then consider fancy tempura (typically inexpensive proletarian food served from stalls) for his/her introduction to Japanese haute-cuisine. To each his own, I suppose. Good luck.

(Edited above: Kondo, not Kanda)