Nicholas Lander eats at Yumi, perhaps London's most authentic and personable Japanese restaurant

Since my first and, regrettably, only trip to Japan I have come to appreciate the enormous gulf that separates Japanese food eaten there and in the West.

It is not a question of the variety of the fish or the dexterity of the sushi chef. California, New York and several spots in London (most notably Sushi-Say, Kulu Kulu, Shogun and Nobu) have yielded excellent sushi and there is, as of last week, a new branch of Nobu in Paris.

The differences are more fundamental, involving the very freshness of the ingredients, of which the Japanese are rightly obsessive; the ubiquity of the sea; the importance of custom; the change in the seasons; and the service which, as a man, I have to admit I find entrancing in Japan itself. I never thought I would experience any of these again without a long journey, that is until last night and the unforgettable pleasures of a kaiseki meal at Yumi, London W1.

Yumi would not look out of place in downtown Tokyo. Although its frontage is very wide by Japanese standards, it looks a bit down at heel from the outside and its interior does not seem to have undergone much improvement since it first opened in 1975. On the way down to the basement dining room the personalised whisky bottles in rows behind glass counters and the shoes neatly arranged outside the three tatami private dining rooms strongly reinforce this impression.

The most significant event in this restaurant's history came in 1985 when it was bought by Yumiko Fujii, or Fujii-san as she is known within its four walls, a woman who combines a charming, youthful giggle with an extensive knowledge of Japanese food and custom and an acute eye for detail. What distinguishes Yumi from its London rivals is not the precision of the service but the relaxed nature with which it is delivered and the personal nature of its surroundings – the walls, for example, are decorated with framed collections of Japanese tortoiseshell hairpieces that once belonged to Fujii-san's grandmother.

And, most importantly, Fujii-san's detailed knowledge of her market. In between our nine-course meal she explained how, contrary to most London restaurants, Sunday evening is her busiest, thanks to the customers who have flown in from Tokyo. (Business apparently gets quieter later in the week after their return.) Supplies are air-freighted to her twice a week from Japan and she supplements these purchases with fish from France and Belgium. Fujii-san strongly lamented the lack of seasonal variety in the offerings from British fish wholesalers.

Such knowledge was gratefully received as only one of our party spoke Japanese and, although I had Richard Hosking's indispensable 'Dictionary of Japanese Food' (Prospect Books £12.99) by my side, the menu, exquisitely wrapped in blue ribbon, was suitably inscrutable.

One of the attractions of such a kaiseki menu over and above a degustation menu offered by a French chef or the tasting menus increasingly popular in New York and London is that the menu, by tradition, follows a rigid pattern of differing cooking techniques that starts with the appetiser, moves on via a clear soup and sashimi to a grilled dish, followed by something deep fried before a simmered dish and finally on to the meal's main ingredient served with rice. The course of a kaiseki meal involves therefore not so much discussing who has chosen the best dishes but which technique the chef has accomplished most successfully.

The appetiser, a timbale of finely chopped scallop, prawn and squid whose flavours were sharpened by a sauce of Japanese apricots, was suitably stimulating whereas the clear soup that followed, made from cured bonito stock, shaved burdock and thin slices of pork fat was pure nourishment and highly restorative. There then followed one of the evening's highlights, sashimi of lobster and blood clam with the purest, most pungent, unusually textured and therefore most expensive wasabi, served on a dish of crushed ice.

The grilled dish which followed, a piece of salmon topped with salmon roe bound in egg which had cooked under the grill produced the highest praise as it encompassed such differing textures: crispy salmon skin, flaky salmon flesh and the crunch of the eggs within the barely cooked egg. It was definitely one of the high points and perhaps explains why the deep fried anchovy and taro paste wrapped in nori seaweed which came next tasted slightly bland by comparison.

There was nothing bland towards the crescendo of the meal: small cubes of sea bass braised in a stock thickened with arrowroot and three kinds of Japanese vegetables; vinegared, fried micro whitebait and shredded cured bonito and a main dish comprising three small slices of duck teryaki with miso soup, vegetables and pickles (this was deemed to be the amin course because it was served with rice without which the meal would not have been complete).

I have always been ambivalent about Japanese desserts and a bowl containing cubes of wax gourd braised with white wine and aubergine braised in red, whilst cleansing, did nothing to change my opinion.

With a bottle of sake at £40 my bill came to just over £100 per person. This was certainly expensive but unforgettable and no more than the equivalent with wine in a top French restaurant.

And for three hours Yumi had transported me back to Tokyo, an illusion that lasted whilst Fujii-san and her staff bowed us out of her restaurant. But only until the first taxi stopped. The driver was not wearing white gloves, the uniform of Tokyo taxi drivers, and he could not take us where we wanted to go as he was 'only going south of the river guv'nor'.

Kaiseki dinners from £70, 80 or 90 per person. A la carte £50.

Yumi, 110 George Street, London, W1U 8NX, (+44 (0)20 7935 8320).
Open 7 nights 17.30 – 22.00