A new Chinese restaurant in Soho? Why bother? Since Soho is separated from the sprawl of Chinatown by a single avenue, you'd imagine the district was a little over-subscribed with the things. But Ba Shan sets out to be something different from the predictable Gerrard Street fare of wind-dried duck, chow mein and dim sum. It's the new brainchild of Shao Wei, who brought the Bar Shu and Baozi Inn to London, and Mr Wei is big on authenticity; he goes to the extent of flying gen-u-ine Chinese chefs in from northern provinces such as Henan and Shaanxi, as well as the over-familiar purlieus of Sichuan. He has linked up with Fuchsia Dunlop, the chef and author of three books on Chinese food, and together they're offering ... Chinese tapas. In case you thought that dim sum was already a tapas style of eating, they explain that they're dealing in xiao chi or "small eats", supposedly roadside snacks sold by street vendors.

To go with this titbit cuisine, the restaurant (in Romilly Street, next door to where Mario and Franco started the legendary Trattoria Terrazza, 50 years ago) emphasises dinkiness, doll's-house cuteness. There are five distinct eating areas, each a tiny room, minimally furnished, although the waitress will enthusiastically point out how strikingly it resembles a Puppet Theatre, a Farmer's Cottage et cetera. You sit on hard stools, eat at tiny tables and admire the way the soft light from the ancient lanterns is accessoried by very modern track spotlights that beam down on the charmingly ancient bird cages. It's a mishmash of fake and authentic China, but is not without charm.

The menu takes some getting used to. For the uninitiated, it's hard to guess the appropriate combination you should order of appetisers, wonton, flatbread, buns, dumplings and the rest; you have to guess your way through. A spicy chicken salad offered shredded chicken with lots of sliced red pepper and a real wallop of coriander, served on a large frisee leaf. The chicken was a little woolly, but the whole leaf-load was marvellously fresh- tasting. Freshly made pork meatballs with water chestnuts and coriander were also sharply tasty little mouthfuls of sausage-meat flavoured with garlic and sage (with a plate of white pepper on the side, like a special delicacy). The only thing was, this didn't seem terribly Chinese: it could easily have been the stuffing in an Easter chicken in Hampshire.

As dinner went on, a simple truth became apparent: you cannot have a Chinese tapas experience on a dinky little square tea-house table. What with the plates of dumplings, each with their dipping sauces, the dry-noodle highlights and side dishes of pak choi, the water and wine glasses (New Zealand Sauvignon, a little overpriced at £23), it became insanely crowded, like the Marx Brothers' ocean-liner cabin in A Night at the Opera.

The food promises a lot – promises above all that it'll be original, never-tasted-before street cooking – but was a touch disappointing. The same five dumpling fillings are offered with either vinegar sauce or "spicy garlicky sauce" but the choice was a little academic because the chicken-and-mushroom dumplings were, frankly, hard to distinguish from the beef-and-celery ones. All you notice is the sliminess of the covering – and the odd colours. I asked the waitress why the chicken was green. "Because it's made from red cabbage," she replied. "So why isn't it red?" I asked. "It's purple," she riposted. "Actually," said my date Yvonne, "it's blue." They're big on colour co-ordination in Ba Shan. They told me they make the beef noodles red, chicken purple, vegetables green, pork yellow and prawns a kind of neutral beige. So at least you know what you're supposed to be eating.

The noodle dishes were fine, if rather dull. My plate of Dan Dan noodles, half-heartedly accessorised with minced pork and soy sauce, was desperately seeking some flavour, while in Yvonne's Sichuan spicy beef with noodles, the mildly piquant beef was carefully surrounded by the tasteless presence of beansprouts, Chinese mushrooms and a very odd-looking Chinese egg.

By the end of supper, I couldn't escape the feeling that this handsome new restaurant, with its cool black exterior and its sweet, doll's-house rooms, needs a firmer hand on the menu. I'm told that some of the dishes I didn't try (like the Pot-sticker dumplings, or the Chaoshou wontons) are a veritable dream of old Xi'an or Sichuan.

What I did try was serviceable, but dull: listless cooking, underspiced, everyday-lunch-in-the-canteen cooking. I'm sure Mr Shao Wei wants to present the down-home cuisine of his birthplace more excitingly than this.

For the moment, it's a restaurant where they seem to pay more attention to the colour of the food than to minor considerations – like how it should taste.

Ba Shan, 24 Romilly Street, London W1 (020-7287 3266)

Food 2 stars
Ambience 3 stars
Service 3 stars

About £70 for two with wine

Tipping policy: 'Service charge is 12.5 per cent discretionary, of which 100 per cent goes to the staff; all tips go to the staff'