I was on the Shinkansen bullet train and roaring north towards the Japan Sea at 200kmh when I passed through the wormhole in spacetime.

The wormhole was on the far end of a long, unlit tunnel. Three quarters of an hour earlier, in the midst of a sunny winter's day, I had boarded the train at the loud, insanely complex and many levelled Tokyo main station, accompanied by my friend Bob Sliwa. We were bound for the coastal town of Kanazawa, sometimes known as the hidden pearl of the Japan Sea and famed for the freshness and variety of its fish-based cuisine.

The trip there last winter was to be the climax of my week-long attempt to find the hidden culinary truth of Japan, beyond the reach of guidebooks or the well-intentioned efforts of celebrity investigators such as Anthony Bourdain.

My secret weapon in this was Bob himself, a man embedded in Japan for 30 years, deeply conversant in the ways and cuisines of the country and, by great good fortune, my college roommate.

We exited the tunnel into a crash of white light. On the far side was a winterscape of deep snow, mountain vistas and blowing wind. The day we had been travelling had until then been dry and mild and the sudden atmospheric shift made it seem that we might, in fact, have just rocketed through a rift in space-time. Bob, stroking his goatee, laughed out loud at my confusion.

"We were climbing in the dark in that tunnel the whole time - didn't you feel your ears pop?" he asked. "What you see here is the result of the steady wind blowing off the Japan Sea from China, picking up the moisture of the ocean along the way and throwing it against the mountains as snow - and lots of it. Think of the Continental Divide, Japan-style."

It is no accident that Tokyo has the highest number of Michelin starred restaurants of any city in the world. But rather than sampling the wares of these warhorses, I had arrived to try the second culinary wave, a quiet in-house revolution that is afoot all over the country.

Driven by chefs mostly in their late 20s and early 30s, its inspiration was the collapse of Japan's mighty economic surge in the early 1990s, followed by the now-famous stagnation, or "20 lost years", as it is referred to in the foreign press.

As the country entered a period of soul-searching, these young chefs took the opportunity to throw off what Bob calls the "legacy exoskeleton" of manners and slavish obedience to groupthink, and instead begin advancing the cause of native ingredients, prepared with great care and what seems, at times, almost freakish originality.

Exhibit A: the plate of smoked, salted cod roe sprinkled with red chilli pepper flakes at a restaurant called N-1155 in the hip, hilly Tokyo neighbourhood of Nakameguro. The smoking and salting produced a deliciously bespoke version of fish jerky, whose peppery marine tang married perfectly with a chilled glass of sauvignon blanc.

Exhibits B and C: a flashcold-smoked sea perch sashimi and a bagna cauda, both served at the same restaurant. Flash-cold smoking, done in the kitchen just before plating, imparts a tangy, cooked woodland savour to the raw flesh of the fish that makes for a delicious cognitive dissonance in the mouth. The bagna cauda was upgraded by having its oil mostly replaced by cream, creating a rich bath into which produce from the restaurant's own farm in southern Japan - thin-cut yellow carrot, mustard green, lotus root and kohlrabi - was dipped and then removed, leaving its bright, vegetal essences enrobed in unctuous garlic.

WHERE FOOD IS THE STAR

The next day, a few blocks away, it was the turn of a place called Harbor Bar. Modelled vaguely on a Venetian wine bar and boasting fish from the Sanriku Coast of northern Japan, the tiny restaurant has a cheerfully casual D-I-Y atmosphere that channels Bushwick in Brooklyn. But there is nothing casual about the food in the least.

The opener was a plate of superfresh scallop sashimi, enlivened with a ginger sauce whose citrus notes gave the dish the feel of a mollusc ceviche. This was followed by a serving of raw botan shrimp - as large as langoustines - which arrived paired with a spicy remoulade of cured carrots.

While we ate, Bob and I continued to catch up. Unusually, for a Westerner who has been living for the long term in Japan, he has lost none of his youthful enthusiasm and manifests the same manic glee he once did as a jazz-mad, art-crazed undergraduate.

"Some people live here and want to be Japanese," he said. "I didn't. Not only is it impossible, but I also don't want to be treated the way the Japanese treat themselves. I love Japan, but I sell myself as a foreigner who's willing to break the rules and say what's wrong."

"And what is wrong?" I asked.

Bob, who works in Japan as an industrial designer, rubbed his hand over his shaved skull and said: "Two words define Japanese culture. One is 'monozukuri', or 'the Japanese way of making things'. The other is 'omotenashi', or 'the Japanese way of hospitality'. If the country rebuilt itself into such a buff economic specimen after World War II, it did so partly out of its belief in the superiority of both of these things to any other country's.

"But then the bubble economy burst, the 21st century happened and the country lost its way. I call it a nationwide case of the rope-adope. Whole industrial sectors have fallen asleep. Remember the Walkman? How's that working out for you, Sony?"

Before I could answer the rhetorical question, my attention was distracted by the arrival of something called an iwagaki rock oyster.

Ah, that oyster. It was the largest bivalve I have seen, with a shell approximately the size and shape of my foot.

"You freeze it while alive and then slow-cook it at low temperatures," the waiter explained, bowing. "That makes the umami come out."

The monster was dressed in a brightly acid dill-based mignonette and disproved the axiom that larger versions of anything taste worse: It was a briny, exquisite splash of the sea in the mouth.

I was still finishing it when the owner of the restaurant, alerted by my exclamations of joy, came over to talk. His name is Akira Matsuoka and he is part of a restaurant consortium that oversees several venues in Tokyo. Rail-thin with high cheekbones, black jeans and alt-rock facial hair, he answered my question as to how he invents his dishes by explaining: "My partners and I think of ourselves as a food think-tank. We don't care about Michelin rankings. First, we come up with the concept, then we invent the dishes to fit it, sometimes collectively and sometimes individually. Rather than a star chef, we make the food the star."

He smiled and circled a finger in the air to indicate the small space crammed with diners. "And it seems to be working."

A FOOD-CRAZED NATION

Back on the train, I heard Bob say, "We're almost here", and I slowly raised my eyes from my notebook.

Kanazawa, like most Japanese cities of a decent size, has a distinct "drinking district", honeycombed with tiny bars and, not long after checking in to our hotel, we found ourselves at a stand-up bar called Choikichi.

Stand-up means exactly what it sounds like and the long counter of this former ice-cream parlour was crowded on a late afternoon with regulars watching sumo wrestling on television. As titans clashed thunderously on the screen above us, the locals chatted happily with one another and I had the sense of having wandered into a tiny Japanese analogue of Cheers, the famously chummy bar "where everybody knows your name". We ate edamame and delicious rakkyo (pickled onions) and drank a fairly common but tasty sake.

Bob, a habitue of these places, was welcomed everywhere we went with shouts. The shouts were particularly loud later that night at a bar named, hilariously, Pub Dylan (as in Bob). There, I was served a very expensive sake called Dassai, whose cool, perfect balance gave me the impression of drinking a dipperful of outer space.

After a quick, delicious tempura dinner, I returned to my dwarf hotel room, only moderately worse for alcoholic wear, and asked myself the obvious question: Is Japan the most food-crazed nation on earth?

Evidence for "yes" is pretty thick on the ground. Tokyo has a staggering 80,000 restaurants, as opposed to the 15,000 of New York and the 6,000 of London. But more to the point: Where else on the planet would a country's biggest boyband have their own cooking show? What other nation would stage a televised competition in which they brought in challengers to try to better a master sushi chef's technique and scanned the resulting sushi pieces with an MRI to compare the ratio of rice to air? What other place could possibly, under any circumstances, have invented the operatic and off-the-wall Battle Of The Iron Chef?

THE LEGENDARY KANBURI

The very next day, as if in answer to these questions, Japan served me the best seafood meal of my life. It did so at a small, easily missed, relatively modest-looking restaurant called Yamashita.

Yamashita is on no foreigner's must-see lists and there was not an English word in sight. But the restaurant, located by Bob, is a temple of sorts where the eponymous owner and chef Mitsuo Yamashita is referred to by his employees as the Master, and boss and staff work as one to pluck the freshest, purest products from the nearby ocean and put them on your plate with minimal interference.

The meal began with a pictorially perfect tray of amuse bouches: thin-cut strips of yellowtail stomach dressed in a vinegar-miso sauce, which tasted smoked though they were not, along with a small pile of herrings fermented in the dregs of sake and a handful of fresh snap peas, each dabbed with tiny blobs of black sesame pesto.

A sake, painstakingly engineered by Yamashita in consultation with local brewers, partnered these refined salty nibbles perfectly. But all this was a mere prelude to that moment when a waitress, smiling, brought in plates heaped high with the prized kanburi sashimi.

Why has this fish been elevated to the very top spot among sashimi lovers? Because kanburi uniquely fuses two qualities that are almost never found in the same animal. Take maguro, the tuna whose sashimi is most recognisable to Americans. There is the red-meat, or akami, version, with its firm texture and relatively mild flavour, and the pinker version known as otoro that is filled with delicious oils and fats. The problem is that the tasty otoro has a crumbly, falling-apart texture in the mouth likened disdainfully by Bob to "eating sashimi marshmallows". Because texture, along with temperature and flavour, are part of the "mouth moment" of Japanese cuisine, the challenge is to find a firm fish that is also rich in oil.

Enter kanburi, which, for that brief, miraculous period every winter, is both those things. The fish, in thick slabs, now lay fanned out on the plate before me, glistening with oil - oil that had leached out of it because the Master had intentionally let the fish "rest", or cure, for a day or so. Mind you, fish oil like this has nothing "fishy" about it. The kanburi was silky, pliant, yielding and tasted of a distilled, superclean essence of the sea. It seemed to exemplify everything that was best about Japanese cuisine and, mouthful by mouthful, it put me into a kind of trance.

A FAMILIAR FEELING

After an elaborately choreographed goodbye, we took a digestive stroll in the seaside air, passing through the gaudy Kanazawa downtown with its Ginza-style flashing lights, its kuru kuru (conveyor belt) sushi restaurants (Japanese is rich in onomatopoetic words and "kuru kuru" is the sound of a conveyor belt; say it fast and you will understand), knickknack shops, bars and omnipresent FamilyMart convenience stores.

Our destination was the beautiful old wood-fronted part of town called Higasha Chaya-Gai. (Kanazawa shares with Kyoto the distinction of being one of the few large Japanese cities not bombed by the Allies during World War II). There, we entered a sleekly minimalist bar called Teriha and seated ourselves among the drinkers, conscious that it was our last evening out.

I had spent a full week living inside a kind of tone poem of fish and alcohol, enriched by unflagging conversation with a dear old friend. But a vague perception had been weighing on me constantly during the trip and, suddenly, in the dark bar, that perception sharpened into words: I've never been to so foreign a place that felt so deeply familiar.

Differently from an Asian country such as India, where I have also spent time, the social iconography of Japan is profoundly recognisable to an American. Despite the culture's insularity and remoteness from us, the Japanese often dress and style themselves in a way that clearly states their social membership in categories of rocker, matron, intellectual and so on, and these identities can be easily "read" by a tourist from the United States. This fact, a product of the long-standing symbiotic relationship between the countries, produces a visual halo effect, in which one is always observing roles and mores on several levels at once. Exhausting on the one hand, it is endlessly, compulsively fascinating on the other.

NEW YORK TIMES