I returned from Tokyo two months ago but I had to wait until now to write about it, because I needed to calm down. For several days I could think and talk of nothing else. It has been a struggle, writing my weekly reviews in between, not to bang on constantly about how much better everything is done in Japan. How the best food that is available in England would not be served in Tokyo to a cat.

But I mustn't. For there is nothing worse than a fresh convert to a country, a cuisine, a religion, suddenly telling you that everything you have ever done is laughable, clumsy and blasphemous.

There isn't room, here, even to begin to scratch the surface of what astounded me about eating in Japan. No, wait, perhaps there is, just. After all, I was only there for 59 hours.

But I can't write through. I can't hope to weave a narrative whole out of it in such a way that your Western, your geijin ear could grasp it. Japan isn't like that. All is simplicity, all is brevity. The painting, the poetry, the music, the food.

So I will give it to you in little pieces. Like sushi.

A grey mountain
The whisper of cool fish
On your hot tongue

Only kidding. I haven't got it so bad, I think I can do haiku.

My hotel room has a smart loo. Seriously. It is more intelligent than at least half the people currently working in London as waiters. The seat is warm when you sit down. It oscillates after a period of inactivity. When you have finished, a control panel offers "front cleaning" and two different levels of "rear cleaning". After the probing jets of just-right water (Heston Blumenthal has not a finer feel for the perfection of temperature), warm air blows you dry. When you stand up, it flushes.

My bum has never been so clean. I have not yet eaten a morsel in Japan, but if they take this much care of your food on its way out, imagine what care they must take on its way in.

Tsukiji fish market is the biggest in the world and easily the size of a small town, like Rome. Just before five on the first morning I meet Mr Yamamoto, executive chef of the Mandarin Oriental, who has secured me a pass for the tuna auction.

He tells me to walk straight and never change direction unexpectedly because of the electric trolleys. They come from behind, rapid and silent, a driver standing upright at the wheel, and they do not stop. Once, once, I step sideways to avoid a puddle ­ there was a screeching behind me, and screaming, and boxes going over and loud cursing, and Yamamoto yanking me away from the aftermath.

The tuna auction hall is as big as a football stadium. On huge pallets, hundreds of tuna, big and smooth and shiny as blue-black motorcycle sidecars fresh off the line. Heads removed, exposing the cavernous space of the collar (a ten-year-old could climb inside). Tail chunk squatting by each body to provide indications of colour and fat content. A gash in the side for similar. Men in blue overalls and rubber boots (I am in Converse, and my feet are frozen), with a torch in one boot and a metal hook in the other. They roam among the fish, probing with their hook at the gashes, peering in to the fish's dark interior with their torches.

Then the clatter of a bell. A man standing on a box starts shouting. A cacophony of other men replying. The bell rings again. Two men spring into the picture with a cart, six men hoist the fish aboard and off the two men run. £30,000, maybe £40,000, has changed hands for this fish. By lunchtime it will be sashimi. Sooner, maybe.

Still at the fish market. Beyond the tuna stadium, acres of "living" fish in blue plastic boxes full of water, pipes lead in and out of boxes, aerating: halibut stacked like pancakes, gently rippling; eels of all sizes writhing; the odd shark, tail-flicking in its tub; dog and catfish, cod, bass, bream, plaice, yellow tail, red snapper, scorpion fish, red and spiked and furious, ranks of them, gasping for oxygen, flipping and popping in boxes; and fish a metre long and spike-nosed that are gold and petrol-blue like a mackerel crossed with a javelin; and also fugu, the big-deal blowfish which is said to kill you if the sushi is not cut right (geijin journalists make a big deal of it), swimming sadly, big as cats, costing 60 quid a kilo.

The market is full of sushi bars, serving the freshest sushi in the world.
Mr Yamamoto likes Daiwa. I have never eaten better food anywhere. Wooden like the inside of a sauna but cool with the dawn air, it has two sushi masters and stools for ten people at the bar. The staff shout their greeting as we walk in. Green tea and a tall bottle of Asahi. Two small, frosted glasses. Pouring for each other, Mr Y and I, never for ourselves. The other eaters are fish-truck drivers in blue overalls, a couple of salary men, a lone student.

The fish pieces are giant, completely covering the rice, which is visible as a bump under the flesh blanket. The older of the two chefs (his son has a restaurant next door but Mr Y visits only the father) keeps it coming, one piece at a time, lifted over the counter and pressed on to the wood before me with a muffled "hai!".

A piece of pale, buttery toro, cold and firm on warm rice ­ the crucial juxtaposition, barely findable in London, where it is often reversed:
room-warmed flesh on fridge-cold, gritty rice.

A pile of golden urchin piled on rice with a seaweed perimeter. The same treatment for cod sperm ­ thick and white and creamy, piled high. The truckers stare.

"They haven¹t seen a geijin eat this before," says Yamamoto.

I'd have feared it was a dawn joke played on the white boy and they've never seen a Jap eat it either, if it hadn't tasted so fine.

Raw squid bound with seaweed; the same topped with urchin; raw prawn, barely dead, the head whipped off, pressed with the flat of a blade and tossed on a grill; the shell peeled off, I chew the translucent silver body and then the head, pink from the heat, is served, which I crunch down; mackerel; warm, yellow eel dressed with a dark slick of something humming with "umi"; octopus slivers with salmon eggs on top; squid, melting and slippery with a mild smoky body of flavour; scallop...

The raw fish is tongue-like, fleshly, so alive. Having it in your mouth is like kissing, not eating. It becomes part of me so effortlessly. It's like we're eating each other. And I just keep thinking, I could come and live here, give up everything just to eat this breakfast once in a while.

Later, looking for tempura at three in the afternoon, I spot a place called Ten-Ichi in the guide book. An hour later I have not found it. Tokyo has no street signs. And what's more they're in Japanese. A neat Japanese woman in jeans and a jacket, about my age, carrying a portfolio asks, "Can I help you?"

I tell her about the restaurant. She says she does not know it but will walk me to the right street. She says that even for the Japanese navigation is difficult, let alone for geijin. Then she puts her hand over her mouth and laughs.

When we fail to find the correct street, Setsuyo goes into a tailor's shop to ask the way. For five minutes I watch them discuss it, turning the map round and round. And then the guy comes out, puts a sign on the door which, I guess, says, "Back in five minutes", and walks us there himself.

Ten-Ichi, original, 70-year-old restaurant of a small chain. Setsuyo won't eat, but sits with me to help me communicate with the chef. The place is a stone-floored, bamboo maze of paper-walled rooms. Waitresses are in traditional kimonos of the hardcore variety, with the big boxy things on the back, standing on the other side of the room's threshold, unstirring until beckoned.

It is just Setsuyo and I sitting opposite a chef with a huge sunken basin of boiling oil. A tiny, spidery shrimp with long feelers is dipped in batter then dropped into the oil with 2ft steel chopsticks; seconds later it is out, and I'm eating it. Then conger eel, spread little fillets given the same treatment and served with a dipping sauce and a sprinkling of curry powder; two asparagus spears; sliced lotus root; two small green peppers.

Eventually comes kaki-agi ­ the symbolic final dish, Setsuyo explains. It means something like "last bits fried", and is a single beignet, a sort of tangly bubble and squeak of prawn and scallop. But then, meaning something else, a bowl of the darkest miso soup containing beautiful tiny clams, no bigger than the rivet on your jeans.

The chef approved of my eating habits (as the drivers did at Daiwa ­ they like a glutton here, I guess) and said I was no "nekochita", which is a "a person with a cat's tongue" and has to do with being finicky, I think.

In Asakusa, in the shadow of a major temple, I saw a restaurant that served only "tonkatsu": I have no idea how to write it. Setsuyo (who, having little to do, has offered to guide me round town) pumped it into her translator calculator and got "wiener schnitzel". But it is made from pork, not veal. It was all they served. Just a little place. Wood and paper walls, a man frying, his wife serving, one old man reading a paper and smoking while he drinks a beer, another reading pornographic manga while he eats.

In Tokyo, any restaurant that is any good serves only one thing.

Nearby, a tofu restaurant. Only tofu. We nip in for a taste. Suddenly, I get tofu. "Must be eaten same day is made," says Setsuyo. "Like bread in UK." And I should weep again, this time for the tragic gap between Setsuyo's imaginings of British eating traditions and the long-life, pre-sliced, refrigerated modern reality back home.

That evening, more sushi, somewhere else, no name I could read. A moody-looking Russian hooker sitting with a pasty-faced local takes a mouthful from a plate of plaice sushi featuring cuts from three different parts of the fish and suddenly cheers up immensely.

Still at the evening sushi, ten "salary men" emerge from a room and put on their shoes. Leaving, each one bows to the sushi master behind the counter.
The last one hands him a huge present and says something long and formulaic-sounding. I ask Setsuyo what he said.

"He said, 'I'm sorry this is such a humble present, it is all I could find.' It is what we always say when giving a present."

Pause for a minute. And try to imagine Alan Sugar, after a routine business dinner, giving a present to the chef. And apologising for it.

A random pub — or Izakaya — this one is a Yakitori pub. All the pubs specialise in a certain kind of food. A guy brings two of those dinky glasses for our crisp Asahi beer. I say how good it is to drink beer like this from such small glasses, so that it stays cool and lively. The guy asks Setsuyo what I said, and she tells him, and a couple of minutes later he comes back with two glasses, wrapped in tissue paper and hands them to me, and bows. The present is comfortably more expensive than the price of the beer I drink and the two skewers of duck's gizzard I eat.

On my third, and final, morning, eating breakfast in my hotel kimono in my room on the 38th floor of the Mandarin Oriental, I glanced out over the nightmarish twist and strain of traffic that tangled from horizon to horizon, and noticed that there was blue sky for the first time, instead of the grey veil that had hung over the city since my arrival.

And then I noticed the violet humps of hills in the distance, beneath white clouds. And then the clouds moved a little and I saw a higher mountain. The top of it flat and covered with snow. My jaw fell, literally, open. Food fell out. I could not have been more awe-struck if I had been looking on the face of God.

Suddenly I was in Japan. Suddenly I was painted blue on a plate, by a stream, under a cherry tree in blossom. I glanced away to pick up a napkin, and when I looked back, Mount Fuji was gone, swallowed up again by the cloud.

Nobody else I spoke to had seen it for weeks. Some didn't believe me. One told me it was good luck.

Japan was once so exotic that Gulliver came here (Part III, "A voyage to Laputa, Balnibarbi, Glubbdubdrib, Luggnagg, and Japan"). He stayed in Edo, which became Tokyo, and was gone several years. I got here in 12 hours, stayed for 59, and left. But by the time I got back to Heathrow, and was immersed again among the fat, track-suited, burger-eating, foul-mouthed, cultureless beasts that are my compatriots, I felt very much as Gulliver did, returning from the land of the Houyhnhnms — disinclined to retake my place among the Yahoos, or to admit that I was one of them.

In the long delay before the luggage arrived at the carousel I went to the loo and was appalled, when I'd finished, to note that it had neither the wit, nor the decency, to flush itself.

Ten-Ichi
6-6-5 Ginza
(on Namki Dori)
Chuo-ku, Tokyo
(00 813) 3571-1949
Set lunch from £35

Daiwa Sushi
Building 6 Chuo-ichiba
5-2-1 Tsukiji
Chuo-ku, Tokyo
(00 813) 3547-6807
About £15 a head

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