'To find someone dishing up kaiseki almost flawlessly just off Queensway is a bit like finding Maria Callas warbling away in Stringfellow's'
I'm bedazzled and occasionally bewildered. Every dish that's arriving – tiny, but perfectly formed, each on a distinct and beautiful piece of Japanese crockery – offers something to make you shake your head in wonder and curiosity. Shavings of katsuoboshi (dried, smoked tuna) on mustard-dressed rape blossom, trembling and dancing in imperceptible air-draughts; or raw sea bream bathed in a sauce of swampy richness that turns out to be made from ankimo (monkfish liver), the sea's foie gras. Or nigiri sushi, the fish cut with forensic precision and served with a little brush for painting on soy sauce made in-house by the chef. Did you get that? Homemade soy sauce. They grate their own fresh wasabi, too, and serve it in a tiny bowl-spoon so exquisite, it makes me consider a spot of light shoplifting.
Fossicking about in a pottery beaker of chawanmushi (egg custard) of improbable delicacy and lightness, I find slivers of eel, wood-ear mushrooms, barely-cooked prawns, ginko nuts: an enthralling mini treasure hunt. There's sashimi that's less raw fish and more artwork: razor clams without a trace of rubberiness; cubes of ruby tuna, plus supremely fatty minced chu-toro that floods the palate with luxurious, clean fishiness; small prawns so fresh they feel like biting into clotted cream. Even garnishes are exciting: tiny branches of baby shiso leaves, foetal coriander, togarashi, glutinous yam paste.
We're wallowing in kaiseki-ryori, Kyoto's haute cuisine. Designed to please the eye as much as the palate, they're meals of lyrical perfection, celebrating seasonality and locality long before any check-shirted dudes in Portland got in on the act. In Kyoto, I tried to book some of the most venerated kaiseki restaurants only to be told in no uncertain terms that they weren't for foreigners. So to find someone dishing it up almost flawlessly just off Queensway is a bit like finding Maria Callas warbling away in Stringfellows.
The couple who run the Shiori, chef Takashi Takagi and his wife Hitomi, used to own a minuscule, acclaimed sushi joint in shonky old Drummond Street (apparently, they plan to open a Japanese tableware store there; maybe I'll buy that spoon and save my immortal soul). But Tagaki's background is in the art of kaiseki: he trained in Kyoto, and worked at London's rarefied and expensive Umu. In this weeny, paper-screen-clad space with five tables and a kitchen that's almost part of the room, he's finally giving vent to his remarkable abilities.
The intrigue continues: nabe, a hotpot made with clear, intense dashi stock in which bob sweet king crab claws, shimeji mushrooms and transparent noodles made from kuzu root starch – these are relatives of the notorious zero-calorie shirataki noodles, but rather more palatable than those rubber-band weirdos. Nigiri in three separate servings, cool fish on room-temperature rice of perfect bite and pearliness, each with its own tiny titfer of dressing: blob of minced truffle, dab of ponzu or preserved plum. Then fondant-textured scallop and tenderised, deeply-scored squid. And, finally, eel, its kabayaki glaze a thrilling, resonating belt of purest savoury.
There's more, but I don't want to wear you out. Especially since we choose to have a different sake with each course, the bamboozling spirit arriving in etched glassware, a different glass for each bottle and served in almost homeopathic quantities (this is no joint for a raucous night out). We try sake that's lightly frizzante, sake aged into caramel-whisky hue, sake from unpolished rice, sake as fresh as crisp green apples… Don't ask me to tell you what they are, all those honjozos and junmais and daiginjos – I remain a fearsome sake noob.
Sure, it's expensive, but good kaiseki is eyewateringly spendy in the homeland, too. Plus there's all that washing-up. At the risk of coming over all M&S, this isn't just dinner, it's a merry-go-round for the senses, a series of revelatory little pleasures. It's an education.
• The Shiori 45 Moscow Road, London W2, 020-7221 9790. Open Tues-Sat, noon-3pm, 6-10.30pm. Set lunch £28.50, £38.50, £50; set dinner £65, £105.
Food 9/10
Atmosphere 6/10
Value for money 8/10