Michiaki, London W1

New Japanese restaurants are often more concerned with looking swish than the quality of their fish, but Michiaki is a happy bastion of traditional values

Even as I am ordering belly tuna sushi, in my mind I am wondering whether to have the salmon or the yellowtail nigiri instead. Nobody has belly tuna. They all say they have it on their menus, and nobody actually does. But the fatty, soft, rich underbelly of tuna, known as toro, and more particularly, the section known as otoro, is the highlight of a sashimi or sushi platter. When you can get it. Inevitably, I will have to sigh and order ordinary tuna from the upper body, or good old salmon. But no, they actually have it. And it's wonderful.

Even as I am ordering belly tuna sushi, in my mind I am wondering whether to have the salmon or the yellowtail nigiri instead. Nobody has belly tuna. They all say they have it on their menus, and nobody actually does. But the fatty, soft, rich underbelly of tuna, known as toro, and more particularly, the section known as otoro, is the highlight of a sashimi or sushi platter. When you can get it. Inevitably, I will have to sigh and order ordinary tuna from the upper body, or good old salmon. But no, they actually have it. And it's wonderful.

It's not even frighteningly expensive, just mildly shock-inducing. For £5.60, you get two generous fingers of alabaster pale toro draped over really good, lightly vinegared, warm rice. This is tuna as meat, sharing the richness and melt-in-the-mouth characteristics of marbled kobe beef.

Already, with my first mouthful, I am fond of Michiaki, the three month-old Japanese from the ever-reliable Royal China group, which also owns the communal sushi and noodle bar Satsuma, in Soho. But where Satsuma is young, fast and minimalist, Michiaki is sleek, dark, moody, and a place to linger. It also showcases a wide variety of Japanese cooking with three different dining areas: a long, sweeping sushi bar lined with red-capped chefs, a semi-separate teppanyaki grill room, and a stylish dining room overhung with large, drum-shaped lanterns.

Chef Naoki Hoshino, formerly of the Michelin-starred Suntory restaurant, has put together a vast menu studded with Japanese classics as well as a few eyebrow-raisers that reflect modern eating trends.

I can't say that either black cod in sweet miso with marinated ginger, Japanese chilli and brandy coffee chestnuts; or the special maki roll with teriyaki yellow tail, smoked salmon, cheddar cheese, asparagus and sun-dried tomato leap up to be ordered. Instead, I relish the idea of taking Japanese cuisine back 100 years with an enchanting clay teapot (dobin) of dobin mushi (£4.80), a subtle, clear broth flavoured with lightly cooked chicken, mushroom and prawn. Traditionally, the juice of sudachi - a yuzu-like citrus fruit - is added, but here a little wedge of lime does the job.

But it is the raw food, ironically, that tells you the quality of the kitchen. A post-Nobu arrangement of salmon and tuna tataki (£13.80) is a pretty scattering of vibrant, translucent, velvety slices of fish very lightly seared around the edges, ready to dip into lemony ponzu sauce. There are dibs and dobs of garlic miso and tiny little jewels of masago (smelt roe)

The line between good and bad tempura is fine, but Michiaki stays high and dry. Its tempura is unusual, the food being wrapped in rice paper before being dipped in the necessarily clumpy egg yolk/iced water/flour batter. This enables them to gather separate ingredients together such as prawn, crab, spring onion and rocket, in an ebi kani tempura (£7.80), which is fun. It's a virtual spring roll, lightly golden with a soft/crisp texture, lifted by a knockout dipping sauce of soy and chilli.

The generalist nature of the menu makes it easy to dabble in the various departments of Japanese cuisine, although I draw the line at teppenyaki, which somehow manages to make everything taste the same.

From the charcoal grill comes ebi teriyaki (£11.50), a single, large split king prawn, and also iso yaki (£5.50), a razor clam grilled in its lovely long shell. I can't cope with paying £11.50 for one prawn, but at least it has flavour and sweetness. The razor clam is fresh, but loses its mojo by being chopped into small pieces.

I have always liked the action-food aspect of Japanese cooking, so am very happy to cook my own beef and vegetables (gyunuki yasai, £16.50) on a hot rock. In the past, this has meant an actual rock searingly hot. This "ishi yaki" is not a rock at all but a bit of bathroom marble placed on a brazier over a lump of blue gel. It's not actually very hot, which defeats the purpose of hot-rock cooking. Just as I get it hot enough to sizzle the meat, the gel runs out and I need another one. Bor-ing.

Hot sake is presented in a deliciously long-spouted pot, and chilled sake, is dazzling in its glass amphora sitting snugly in a canister of ice. Dangerous stuff, but nothing goes better with the light clean flavours of sushi. For the beef I move to a plummy 1999 Mondenet Vieilles Vignes Brouilly (£27) from a South African, Chilean and French list.

The sake fallout is such that I find myself ordering dessert, not something I would do if I were in full possession of my senses. Satsuma and pomegranate cheesecake (£5.50) turns out to be of the Jewish baked variety, a bit overcooked and wrinkly.

Restaurants such as Michiaki are increasingly hard to find in a world of machine-made sushi and big-money fashionista neo-Japanese restaurants popular with high-class hookers (well, that's what they look like). This one sits happily in no-man's land offering an interesting, diverse, fine quality Japanese dining experience, something we need more than we need conveyor belts and circuses.

14 Michiaki 40-42 Baker Street, London W1, tel: 020 7486 3898. Lunch and dinner are served Mon-Sat. Around £115 for two including wine and service

Scores 1-9 stay home and cook 10-11 needs help 12 ok 13 pleasant enough 14 good 15 very good 16 capable of greatness 17 special, can't wait to go back 18 highly honourable 19 unique and memorable 20 as good as it gets

Second helpings: More Japanese all-rounders

Niji 64 Thistle Street, Edinburgh, tel: 0131 226 7567 Set in a smart but minimalist space, this friendly Edinburgh restaurant dishes up a great variety of classic Japanese dishes in a Western-style, three-course format. As well as all the usual sushi, sashimi and tempura, you could try chawan mushi (savoury egg custard with prawns), salmon teriyaki or yakiniku beef. Finish on sake sorbet with poached pear.

Koo 127 Old Street, Ludlow, Shropshire, tel: 01584 878 462 This charming little Japanese might not be the first thing that comes to mind when discussing Ludlow's formidable reputation as a food destination, but it's a big hit with the locals. Popular orders are sushi, gyoza dumplings, karaage (crisp, fried chicken) and sake itame (baked salmon parcel). There are also take-away bento boxes, handy for the annual Ludlow Festival.

Matsuri Mid City Place, 71 High Holborn, London WC1, tel 020 7430 1970 Here, under one very designer roof, you can sample everything from sashimi to sushi, kushiage to karaage, tempura to teppanyaki. What's more, you can choose to sit in the main dining room, at the sushi counter, downstairs in the teppanyaki room or at the bar where you can enjoy "Japanese tapas" with your drinks. If the à la carte menu daunts you, try a set menu.

Email Terry Durack about where you've eaten lately at t.durack@independent.co.uk