FIRST, A LANGUAGE lesson: it's pronounced 'nik-ay'. Next, a history one: 'Nikkei' literally means a Japanese person born outside Japan, yet it has come to encapsulate not just the people, but the food that Japanese emigrants and their children cooked – first in Peru, then Brazil and Argentina – in the late 19th century and throughout the 20th.

There it stayed, populating the restaurants of Lima and São Paulo with tiraditos (a Nikkei take on Peru's ceviches, where the fish is sliced like sashimi instead of cubed), until now. Well, a bit before now to be precise. The last three years has brought a new wave of Nikkei-inspired restaurants, not just to London, but to the world stage. There's Pakta, Albert Adria's place in Barcelona, Maido in Lima – 44th best restaurant in the world according to the World's 50 Best Restaurants awards this year – and La Mar at Miami's Mandarin Oriental. But it's London that has really embraced and evolved Nikkei's many charms. When it comes to Nikkei in the capital, fusion is no longer a dirty word.

In the beginning

It started with two restaurants that ostensibly have as much in common as burgers and braised short-rib; Ceviche in Soho and Sushisamba atop the Heron Tower in Liverpool Street, which both opened in 2012. Despite their differences, they share a strand of Nikkei DNA.

For Martin Morales, founder of pioneering Peruvian eatery Ceviche and its subsequent spin-offs Andina and Ceviche Old Street, Nikkei is "a pillar of our cuisine, something I grew up eating in Lima. It's part of my story." So much so that he has named one of his most famous dishes – a tiradito of raw salmon garnished with tomatoes, spring onions, rice noodles and a 'tiger's milk' curing liquid bursting with lime, orange juice, ginger, soy and mirin – 'Sakura Maru' after the first ship to bring Japanese emigrants to Peru in 1899.

It appeals to Londoners' sense of adventure. Diners here are looking to be transported

Morales thinks Nikkei's profile is rising because it fits with the current verve for communal eating and sharing plates, but also because of its abundance of healthy raw options; whether it's zingy salads or the many maki, tiradito and ceviches. More than that, he says it appeals to Londoners' sense of adventure. "Diners here are looking for a moment of magic, for transportation to another place. Nikkei offers that."

The London Foodie

The London Foodie

Food writer, chef and now published author Luiz Hara, aka The London Foodie, is one of the foremost authorities on Nikkei cuisine in London. Click here to see a recipe from his new book Nikkei Cuisine: Japanese Food the South American Way

For Claudio Cardoso, executive chef at Sushisamba, where hordes of glitzed-up diners are wowed daily at altitude by the fusion of Brazilian and Japanese fare, it's the perfectly balanced flavour profiles of Nikkei dishes that turn the key of success for restaurants. "It's a cuisine that suits every palate. Not too salty like Chinese or too rich like French. It has something for everyone – salt, lime, chilli, sweetness. It's just right."

Next came Chotto Matte, the breakaway restaurant success of 2013 from Kurt Zdesar, the man behind Nobu London, Hakkasan and founder of Ping Pong, who took this Goldilocks formula and, along with executive chef Jordan Sclare (Nobu, Buddha Bar and Aqua), ran with it. Sclare and head chef Michael Paul call themselves 'The Nikkei Boys', and even have their own YouTube vlog where they post kitchen capers and clips of celebrities cooking with them. They're the hashtag generation's answer to Nikkei, fast becoming a brand in their own right.

View on Instagram

Sclare is the first UK chef to wade in and make Nikkei a destination cuisine (as in, 'Shall we go for Italian tonight? 'Nah, I fancy Nikkei.'). They're the faces of new cooking, and their food is so good no one cares if they are neither Japanese nor South American. "The Nikkei food in London right now has a new spirit. It's the next generation of eating," Sclare tells me. "It doesn't have to be fine dining, it just has to be bright and powerful. It has to create a party in your mouth."

Another man on board the culinary carnival is Luiz Hara, brought up by a Nikkei family in São Paulo, he now runs the London Foodie blog and has been hosting Nikkei supper clubs for two years. His cookbook, Nikkei Cuisine: Japanese Food the South American Way (Jacqui Small, £25) is the first Nikkei cookbook published outside Japan or South America and is out this October.

"When I first started doing supper clubs they were purely Japanese, but I started cooking Nikkei when I realised London was hungry for something new. Diners here are incredibly curious, always on the lookout for something different," explains Hara.

Nikkei, like the Venetian tapas and small plates trend that's still in play years after the Polpo effect of 2009, is not just another food fad. "It's the next big thing in food because it has the unique benefit of being both authentic and exotic," he says.

Here and now

After the initial flurry of openings between 2012-14 (which also included UNI near Victoria and Lima in Fitzrovia), Nikkei has had a few years to brew in the London food scene. But 2015 has seen a further evolution in what Paul Sowden, head chef at Nikkei's latest home Mommi in Clapham, calls "gastronomic natural selection at its finest."

The two biggest Nikkei openings this year, takeaway and fast-casual dining hotspot Amaru in St Katharine Docks and café-cum-local restaurant-cum-post-gym-hangout Mommi, have put a more casual spin on Nikkei, taking it away from the soul cooking or glam-rock outposts of its initial incarnations and putting it firmly in the hands – and mouths – of the mainstream. This, coupled with Luiz Hara's forthcoming book means that tiraditos and sukiyaki (a Japanese hot pot) will soon start appearing on dinner party menus across the land.

"It's a food type so perfectly on point it's almost a cliché – fresh, raw, healthy without the worthiness of a health food," says Sowden. "We don't even use the word Nikkei on our menu, but it's on the tip of everyone's tongue. People are using it on Trip Advisor."

Nikkei cuisine in London – in pictures

Ultimately, Nikkei is flying because it's the perfect cuisine for now. It's healthy and communal, exotic yet with enough recognisable components to be accessible. Crucially, for Londoners and chefs alike, it's also not completely defined yet. There is no end place you can visit that typifies Nikkei, no prescribed set of rules.

Next year, the world will watch as Rio passes the Olympic torch onto Tokyo, hosts of the 2020 games, and a spotlight will fall on two nations already linked by a mesh of culinary cross-cultural references. By then, London will be awash with Nikkei pop-ups, cafes, tasting menus and cocktail lists. Hell, the Nikkei Boys could have kicked Boris Johnson out of City Hall. When it comes to Nikkei, anything is possible. ■

Follow Amy on Twitter @amygrier