I really enjoyed my dinner at Sasaya. You should book with great advance, as it seems to be very famous in Berlin, but we manage to book a tiny table for seven.
On the one hand, the forced us to stay on a tiny table even if we could have moved to another one, which got free while our food was on the way and remained empty for the whole evening. We had to sacrifice a little. Also, the service was not so fast.
On the other hand, the waitress was nice and understood english (not so common in Berlin's asian restaurant, as I found out). The menu has a great variety and prices are just a little higher than the average, but it is totally understandable. My rainbow rolls were very good, my chirashi was very strange because of the variety and the thickness of the raw fish but good too.
I will come back for sure.