London Japanese Restaurants, UK

Japanese food is one of the great cuisines of the world. Even many countries have imported portions of Japanese cuisine. In the United Kingdom, Japanese cuisine has become quite popular in all medium and major cities, so that it is very unusual not to find one or more Japanese restaurants in London, specially in the center of the city. It is quite easy to find authentic Japanese food restaurants in London. Most Japanese food will contain some fish. Unfortunately, strictly vegetarian food is rare. Here is a Japanese London Restaurant guide and Japanese Restaurant reviews.

The best Japanese restaurant London I have had the pleasure of experiencing was Nobu Japanese Restaurant in Berkeley Street. It’s very gorgeous place. I advice to go to Nobu Japanese restaurant for a special occasion dinner. But it’s very expensive.The atmosphere is lively but not noisy. The 15% 'optional' service charge adds to your bill.
For celebrities seeing I would definitely go London's Best Japanese Restaurants for either the Ivy or Nobu.
The Ivy being more english than the later. Here you can see Stella McCartny.  
Also try Zuma Japanese restaurant for modern jap fusion. For Saturday night dinner you need to book at least two weeks in advance. It isn't traditional Japanese, and not what you expect but you should be pleasantly surprised. If I you want to eat sushi London,  sashimi etc I should go to Yo! Sushi. Honestly, the Nigiri and Maki I've had at ITSU are not much different and a tenth of the price.
Sumosan Japanese restaurant in Mayfair, not quite Nobu prices but pretty expensive. The fish quality is great. Be sure to try sashimi salads.It is very difficult to get good value for money for Japanese in London .But Sumosan is in line with most Japanese restaurants in London with respect to price.
Misato Japanese restaurant is near Piccadilly Circus. This place comes to mind whenever I look for reliable and fuss-free traditional Japanese fare. Japanese rice and noodles dishes are delicious. It’s the really nice food for good price. The portions are huge.
Try Miyama for sushi (their branch in the City also has a great sushi bar) This place comes to mind whenever I look for reliable and fuss-free traditional Japanese fare.
Yo! Sushi aren't my favorite sushi restaurant London
If you want to spend less, fill up on a noodle dish to start with. Gili Gulu is a self service restaurant and if they appear sharp this is because the turn around is very high and they are busy. Atmosphere is fun as lots of people are having a good time
The food not so fresh and tasty. But the miso soup is delicious. Good Japanese food in London is generally expensive. Cheap sushi is available in Tesco, Sainsbury's and other supermarkets but you get what you pay for.The largest supermarket chains all carry basic sushi and sashimi, and Japanese ingredients.