Assuming you’re okay with chopsticks (which you are, because this isn’t the 1970s), there are only two really, really important things you need to know in order to enjoy/survive Tokyo.

One is how the toilets work and the other is how the metro works. Nobody told me either. I could have been killed.

The toilets are electric and the instructions are in Japanese, which is an extremely foolhardy combination. The one in my hotel flushed automatically, so, really, I could have just left all the other buttons alone and everything would have been okay.

But the diagram of a pear being hosed fascinated me, in a kind of jet-lagged, devil-may-care way, so, at the second opportunity, I pressed it. I still wish I hadn’t.

A cheeky Japanese monkey

In Japan’s volcanic ranges, man and monkey share the ultimate hot tub. Waldemar Januszczak takes a dip

Lost in sushi: Giles Coren in Japan

In Tokyo, Giles Coren finds all his ideas about what food can be are turned upside down

• Tokyo’s secret master chef

BACKGROUND

• Hook me up with a local in Tokyo

• Tokyo, technology central

• Japan, land of the rising ski star

• Climbing Mount Fuji: land of the rising sun

Related Internet Links

• More than 60 articles in our Japan travel section

Related Links

• Tokyo: The smart guide

A noise came from beneath me, the sort of noise you get in Bond movies just before a laser cuts off someone’s testicles; then, a surprisingly vigorous jet spray. I assumed it would stop in due course but it didn’t, not even after it began to hurt.

I wasted a whole abrasive minute trying to decide whether it would be better to jump off and slam down the toilet lid or stay on and press some more buttons. Eventually, bravely, I went for the latter, opting for the diagram of what looked like a pair of breasts wrapped in a towel. How bad could that be?

The jet moved forward in what I realised too late was a front-bottom-cleaning service (for ladies, not men, obviously). My testicles were now taking the brunt of it, the horror of which I hope at least half our readership can imagine.

The next two buttons only increased the ferocity of the jet. And the one after that started, in car-wash parlance, the wax phase. Only after I flipped open a panel, unscrewed another one and pressed a switch the size of a grain of Japanese rice did the thing finally stop. You’d think they might have mentioned that at reception.

With a remarkably clean bottom, I set off into town, which brought me to my second challenge of the day: the Tokyo metro. But because there is less at stake, I’m not going to explain it for you. It would be like giving you the answers to an exam you’ve studied for all year. I want you to feel the satisfaction of working it out all on your own. Which you will. Eventually.

FOR A FEW YEARS, Tokyo has been out of the Far Eastern limelight. Hong Kong hogged it all, then Shanghai. Tokyo, just that much further with your 31in of legroom, that little bit less on the way to Australia, and infamously expensive, just dropped off the radar. Not that it cared. This is not a place that panders to tourists. It’s just carried on regardless, in its own crazy, discombobulating way.

But now we’re coming back. Michelin inspectors have declared Tokyo the food capital of the world. And, thanks to a lily-livered yen, it’s affordable. But it still isn’t going to go out of its way to help westerners assimilate.

Nothing is in English; nothing happens the way you’d expect; everything is perfectly logical, but not to you or me. As a result, if you want to enjoy/survive it, you really have to throw yourself at it.

At 4.45am on day three, I’ll confess all the throwing myself at it was taking its toll. I was off to eat sushi at the Tsukiji fish market, but I wasn’t in a sushi-eating mood. Despite repeated attempts to nod off the night before, I had eventually given up and spent the small hours pointing at pictures of cocktails in a louche bar called Insomnia.

At various stages, I was morose, introspective, amused at my own mortality, resolved to change everything, resolved to change nothing and determined to learn Japanese. These are the joys of extreme jet lag.

The language barrier wasn’t helping either. At the meal that kicked off the night that would never end – at Hanasanshou, a swanky, recently Michelin-starred restaurant – the waitress taking my order seemed to understand me, so, as usual, I overstepped the mark.

“Can I decide on dessert later?” I asked, pointing at the pictures of desserts.

“Yes, it’s dessert,” she replied. So I blush, because she thinks I’m telling her it’s dessert, which would make me an idiot.

“No, can I choose dessert once I’m further into my meal?”

“Yes, dessert. You choose one.” Just choose one, you idiot, say the voices in my head.

“I was thinking I might have a better idea of the sort of dessert I’d like in an hour.”

“One hour?” She’s getting that frightened look in her eyes while I’m drawing a circle with my finger on the face of my digital watch.

“I’ll have the kuzukiri.” This happens at least five times an hour in Tokyo. “Is the rice enough for one person?” “Rice, yes.” “I’ve lost my metro ticket. Should I buy another one or can I just go through?”

“Ticket, yes.” Until you just resolve to stop worrying about it and order a drink in a cocktail bar.

And that’s how come it was 4.45am, I’d had 40 minutes’ sleep, and I was walking into the great swirling maelstrom that is the Tsukiji fish market in search of a particular sushi bar recommended by a masterchef. First, I played Frogger with thousands of fork-lift trucks in the vegetable warehouses.

That went on for about half a kilometre. Then, things became altogether fishier. I passed an army of fishmongers selling beautiful chunks of deep-red tuna. Further in, the tuna was being sawn up; further in still, the tuna auctions: shed after shed filled with great tuna carcasses and men in wellies looking anxious. I never got as far as the boats. My legs were tired and my hangover was kicking in. What I really, really needed was a feast of raw fish.

EVERYONE knew Sushi Dai and pointed in broadly the same direction. In an alleyway on the edge of the market, I found it, one of several anonymous frontages. I joined a queue. None of the other frontages had queues, which I was pleased about.

The longer I waited in the cold predawn, the more I wanted to retreat to the warmth of my bed and the less I could because of the increasing time I’d already invested. If you see what I mean. After what seemed like 45 minutes but was a mere 40, the door opened. Twenty people filed out looking pleased with themselves and we filed in looking cold.

Green tea and small piles of pickled ginger were spaced out along the bar. The three samurai sushi chefs welcomed us before beginning their flashing bladework. Despite the hangover and the ungodly hour, the first three mouthfuls were perfection: two tuna sashimi and a roll of rice, placed, one at a time, directly onto the bar. Then, a huge shrimp. Some miso soup. Squid legs. The hangover was gone. This is what travel is all about, I thought to myself.

My fellow diners, all dressed as if to set off to their office jobs, which they probably were, chatted away to the chefs, while the guy next to me took it upon himself to translate. His mobile phone had a Japanese-English dictionary.

Mackerel, said the phone. Very nice. Flat fish. Okay. Cod’s roe. It’s a bit early, but fine. Then, something yellow and squishy, soft-tasting, cloying, the sort of thing good eaters like AA Gill give five stars for.

My friend started typing. “It’s okay, I don’t need to know,” I replied, trying to swallow. “Ignorance is bliss.”

He showed me the screen. I looked away, sensing the worst.

“Ovaries,” he shouted. And everyone else shouted ovaries too, just in case I didn’t understand.

Back in the fresh air, I had 14 hours to work up an appetite before my next life-changing meal. So I walked, zombie-like, up and down escalators, through flashing lights, across mile-wide shopping malls, doing my best not to get run over or sold anything electronic and useless.

I had an astonishing episode with a drinks vending machine and found what must be the only pedestrian walkway in the world that has a flyover below it and two above. But I still couldn’t sleep.

The meal I had been killing time waiting for was at Shunju, one of the few places in Tokyo to have Saga beef on its menu. Saga is said to be even more of a delicacy than Kobe, the beef that comes from cows that, like my wife, demand daily massage. I settled into my seat, high above the relentless neon of the city, smiled at the waiter and ordered the Saga. He asked what I would like to drink with it.

“What would you recommend to go with it?” “Yes, a drink?” Resigned, I pointed at hot sake and he brought it out. I took a long sip and receded further into my seat. I can’t remember much about the taste of the beef. I can only remember being amazed. I suppose at that point, it all got a bit too much. How many cities can do that to you in only four days?

Matt Rudd travelled as a guest of British Airways and the Japan National Tourist Organisation

Times recommends

• New York's top 10 new hotels
• A Scottish monastery retreat
• Welcome back to Rwanda