The greats of broth: A bowl of ramen is the ultimate fast food

Now authentic versions of the Japanese staple are starting to fill British bellies, as Tim Walker discovers.

I never much cared for noodles. Too many underwhelming, broth-based Wagamama meals. Too many student-made Super Noodles. I've always resented sending a chopstick to do a fork's job.

But then I was in Tokyo in January, cold and bleary from the 12-hour flight, and I staggered into a ramen-ya for lunch – or was it breakfast? – where I was served a bowl of authentic tonkotsu ("pork bone") ramen: skinny, springy yellow noodles, coated in rich, creamy stock simmered with a pig's backbone, topped with wafer-thin slices of fatty pork belly. You eat them fast, shovelling and slurping, before the noodles get soft, or the broth tepid. Ramen is Japan's doner kebab, its bacon sandwich; a jet-lag fix, a hangover cure, a drunken late-night snack. While sushi restaurants have a hierarchy that runs from conveyor belts to Michelin stars, ramen is a social leveller. And done right, I discovered, it's delicious.

There are three main varieties of Japanese noodle: udon is a thick, bouncy wheat-flour noodle from the south end of the country; soba is a thinner buckwheat noodle from the north; ramen originated in China, but is now a Japanese staple. Unless you stay up all night preparing your stock, you can't make it properly at home. So when I got back to London, I went googling for a local ramen joint.

Japan has more than 30,000 ramen-ya, and noodles have long been a street-food standard in the US. Last year, leading New York restaurateur David Chang started a food magazine, Lucky Peach, and devoted its entire first issue to ramen (Japanese newsstands often feature four or five ramen mags). But London appeared to be bereft. There was Cha Cha Moon, Alan Yau's Chinese noodle place off Carnaby Street, and Koya, the udon noodle canteen in Frith Street, where I happily broke an egg into a brilliant roast duck broth. But there was still no genuine ramen bar on my radar.

Until last month, that is, when Tonkotsu – apparently the capital's first authentic, Japanese-style ramen-ya, opened on Dean Street in Soho. Tonkotsu ramen is the restaurant's signature dish, but I tried its "Tokyo Spicy" recipe. To make it, the cooks simmer pig bones in stock for 18 hours. They use pigs' trotters, which contain the collagen and bone marrow that thicken and enrich the broth. Then shoulder bones and rib bones and chicken carcasses (to take the edge off the porkiness, I'm told). Three hours before service, in go the vegetables: carrots, onions, garlic, ginger. At the last minute, they add umami-packed, dried tuna "bonito" flakes and sheets of konbu kelp. The garnish is pulled pork-shoulder meat, braised in the stock and mixed with chilli oil, plus seasoned eggs, spring onions, and menma bamboo shoots. The noodles are cooked separately in clean water and, at last, dropped into the stock.

Tonkotsu's chef-owner, Ken Yamada, was born in Shizuoka, two hours' drive south of Tokyo, where his parents ran a traditional ryokan Japanese inn. The family moved to the UK when he was 12 and after university he started cooking in French restaurants. "The difference between French and Japanese stock-making is comical," Yamada, now 36, says. "In France they skim all the fat off; the idea is to keep the stock pure and clear. Tonkotsu is the complete opposite: you need to get everything amalgamated into the stock, so that the end product is thick and creamy. I prefer it, because you don't lose anything; you get it all into the stock and consume it, which is more romantic than chucking the nasty bits out."

Yamada and restaurant co-owner, Emma Reynolds, are also developing a "London" ramen for their menu, which he says will contain egg, smoked bacon and roasted tomatoes. This reflects the vast range of regional variations in Japan. Tonkotsu, for example, comes from Kyushu, the country's southernmost province. The lighter miso ramen, meanwhile, originated in northernmost Hokkaido. The other two major ramen flavours are: shoyu (soy sauce) ramen; and the oldest of all, shio (salt) ramen, which is made with chicken, vegetable, fish and/or seaweed stock. Every major city in Japan has its own signature style. Ramen is not only part of Japan's national identity, but part of its regional identities, too.

It's not clear when, exactly, the noodles were first introduced from China, but there were ramen stalls in Japan by the turn of the 20th century, mostly feeding immigrant Chinese labourers and students. After the end of the Second World War, Japan was flooded with cheap flour from the US. Japanese troops, returning from the conflict in China, brought back with them a taste for Chinese cuisine. The two trends combined to cause a boom in ramen culture and noodles soon rivalled rice as the national carbohydrate.

Barak Kushner is a Cambridge Professor of modern Japanese history and the author of a forthcoming book: Slurp! A Culinary and Social History of Ramen – Japan's Favorite Noodle Soup. Historically, Kushner writes, "The Japanese ate little meat, little rice, little oil, and very little spice. To make, market, and enjoy ramen Japanese society turned its national cuisine on its head in the last half of the 20th century. The Japanese learned to enjoy pork, which they previously despised, and came to cherish a whole panoply of spices. In addition, the influx and spread of Chinese culinary tastes within Japan broke the stranglehold soy sauce had as the one condiment that blessed Japanese cuisine".

David Chang's flagship Manhattan restaurant, Momofuku, is named after Momofuku Ando, the Taiwanese-Japanese businessman who invented instant ramen in the 1950s. Ando began developing the dried noodles (just add boiling water) in 1948, to feed a starving post-war Japan. However, he only hit upon the successful recipe a decade later; instant noodles became popular not as rations, but as fast food for a society on the move. There are now more than 65 million portions sold every year worldwide. Before you go out and buy one, though, find a ramen-ya where you are and try the genuine article.