Like Britain, Japan is an island nation with a deep-rooted fishing tradition. But although we love our seaside cod (or, these days, pollock) and chips, the Japanese obsession with sea-life is in a different league.

Walk around the enormous, sprawling Tsukiji fish market in Tokyo, and you’ll see for yourself: while giant tuna are carved up and auctioned in the wholesale market, the 1,600 stalls sell 450 bewildering varieties of seafood (many of the bug-eyed creatures laid out on ice, or hanging from poles, or dried and packaged, look like they come from a different planet).

If you want to understand Japanese cuisine – particularly sushi; fish in raw, pure form – this is the place to start. But to see how this stuff is transformed into those artful morsels served in Tokyo’s restaurants, you’ll need to seek professional help; which is what my girlfriend and I did, at the Peninsula Hotel.

The Peninsula – a five-star hotel overlooking the Imperial Palace gardens in Ginza, the heart of the city – had just begun to offer a Japanese cookery course, and we were to be the guinea pigs.

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Once kitted out in smart white chef’s smocks (with personalised name badges, of course – the Japanese don’t do things by halves) we were led into a small, gleaming kitchen and introduced to Chef Teruyuki Kojima and Chef Shingo Suzuki. They were a perfect double-team: Kojima the slender, smiley, talkative teacher and Suzuki his serious, attentive, diminutive assistant.

The seafood – bought at Tsukiji that morning – was laid out: tuna, sea bream, squid, two types of shrimp (the armoured grey mantis and the pink sweet variety), salmon roe, clam and eel. We were shown how to cut a bit-size portion of tuna, diagonally, with a daily-sharpened knife, from a block of the glistening red meat.

Incisions were made in the rubbery surface of the piece of squid: a neat trick to make it more flexible, so that it flops over the rice. Everything can be eaten raw apart from the mantis shrimp, clam and eel, which are quickly boiled – the shrimp in water, the clam and eel in solutions of water, sake, sugar and soy sauce, to give them sweet teriyaki flavouring.

At this point we were wondering if the Japanese always took such a hands-off approach to teaching: Kojima, though charming, hadn’t allowed us to actually touch anything yet – the translator explaining that the knife or the boiling water was “a bit dangerous”. But once the fish was ready, and the rice was cooked – and mixed with rice vinegar, sugar and salt – it was time for our culinary dexterity to be put on trial.

For nigiri sushi, the rice is shaped into small bricks, and the fish placed on top.

The trick here is to get the rice to cohere neatly without it all sticking to your fingers – regular finger-dipping in a bowl of cold water and vinegar proved essential. Kojima showed us a series of three precise movements, a little like a card trick: the rice is transferred from hand to hand, squeezed and shaped by index finger and thumb.

A little wasabi is smeared onto the underside of the seafood, and then it’s placed firmly onto the rice. Seeing the tuna hang over the edges, I’m surprised by how little rice we’ve used: Kojima explains that small portions of rice are the sign of a good restaurant: those chunky white pedestals I’m used to are just a way of filling people up so they can be served less of the expensive fish. Our efforts are not as neat as Kojima’s but pretty respectable – and they have a beautifully clean, fresh, sea-bed taste.

Next we try maki sushi. A rectangle of nori (dried seaweed paper) is laid out on a bamboo mat. Rice is spread generously over half the paper (again, the finger-dipping is useful here) and then a thin strip of either cucumber or tuna is laid in the middle. The mat is rolled, wrapping the nori over on itself and containing the rice.

This is Edo sushi (Edo is the old name for Tokyo), pure and simple, Kojima explains. When Californians first Americanised sushi with the California roll (a roll containing crab meat, avocado and mayonnaise, with the rice on the outside) they opened the flood-gates: now Japanese chefs have to steel themselves against the gaudy bastardisations they find outside Japan, including rolls filled with – Kojima grimaces, as if this is a particularly bad joke – cream cheese and smoked salmon.

We’re also shown how to make tempura – deep-fried fish and vegetables. Whiting, shrimp, lotus root and pumpkin are laid out. Kojima shows us how to cut nicks in the tail of the shrimp: this bursts a little water pouch which would otherwise explode on contact with the hot oil. (That sounds like a brilliant YouTube experiment, if anybody wants to give it a go.)

We brush the fish and vegetable pieces with flour and then dip them in a mixture of egg yolk, water and flour before dropping them into a bubbling pan of oil. We drip some extra batter onto the shrimp as it sits in the oil: the mixture hardens and bristles, and a couple of minutes later we scoop the pieces out. Dipped in a cloudy tempura sauce, they are sublime: sweet and crunchy and light.

The lesson is over, and Kojima and Suzuki are eager to show us the professional version, whipping up a mini-banquet of sushi and tempura platters – served in our own private dining room, with a special printed menu – followed by the Peninsula’s trademark creamy mango pudding and accompanied by roasted tea and sweet, crisp Daiginjo sake.

We leave, with much smiling, nodding and thanking, thinking how impressed our friends will be when we casually serve them home-made nigiri and maki back in London. I wonder if Tsukiji does mail order?

The Peninsula Tempura and Sushi Cooking Class

Participants learn to prepare tempura and two styles of sushi, nigiri and maki, followed by a Japanese lunch. Each participant receives a Peninsula apron. The program is from 9am to 11am, and is available for four to six people. The price is £170 per person.

For further information and reservations visit www.peninsula.com or call 00800 2828 3888

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