We were so happy that one of the Japanese ladies that I met told us about this restaurant. Immediately off we went :)
It is in a 5-star hotel called ITC Hotel really close to UB City. The ambience is superb. Although it is located on a ground floor and you don't get to see starry sky or anything, but you get to see a rather zen-like garden through the big windows. Sushi chef is Japanese (yes!), and he assorted sashimi for us out of very limited ingredients he gets (according to him). Of course, you won't get the freshness you get in Japan, but all of them were pretty good. We also ordered some robata type of food (grilled food) . Our favorite was Aspara Buta Maki (asparagus wrapped with a thin slice of pork meat). It is rather a common plate in Japan, but it was rare for us in India as people hardly ever eat pork here. Tempura Moriawase (assorted Tempura) was also good. Overall we enjoyed everything. And, they also had a wonderful display of different sake and shochu! That's so rare in Bangalore, as I heard that from another Japanese restaurant that they could not import sake for a while due to the earthquake.
One problem is the price. Most of the dishes are above 500 Rs. Sashimi platter (regular size) was 2000 Rs. Pretty much double of what you usually pay in Japan (for the served proportion). So, be prepared. It is definitely a place to go for a nice occasion.