We go places in Tokyo with the street-style favourite and creative behind Camoshita United Arrows – now available on MR PORTER.

Swapping a career in architecture for a job on the shop floor might seem an ill-advised move. But it’s one that’s worked out pretty well for Mr Yasuto Kamoshita, creative director of Japanese brand United Arrows. He is also the namesake of the Camoshita (with a C: “K is very Japanese,” says Mr Kamoshita. “Replacing it with the C adds an Italian twist, I think”) United Arrows line, which arrives on MR PORTER this season. Internationally regarded as one of Tokyo’s most stylish men, he embodies the evolution of one genre of Japanese menswear – the Ivy League look.

To explain how he became a style star, we need to take a trip back in time. In the late 1960s, Japan looked to the US for its inspiration as men began casting off traditional and wartime dress. In 1965, executives from a Japanese label called VAN flew to the US where they photographed and filmed American students at Dartmouth, Princeton and other Ivy League universities.

The resulting film and book – both called Take Ivy (a play on jazz musician Mr Dave Brubeck’s “Take Five”) – transformed a classic genre of American menswear into a cool youth movement in Japan. The inroads that were made by penny loafers, chinos, tweeds and madras checks were so deep and lasting that you can still see touches of the look in the way a subset of stylish Japanese men dresses today.

Mr Kamoshita, who grew up on the east side of Tokyo’s Shitamachi (downtown) area, came of age when men’s magazines such as Popeye were popularising this mythic view of American style. After graduating from an architecture course at Tama Art University (one of the most renowned in the country), his love of US academic style ironically led him away from his education (“I grew frustrated with the expressive limitations in architecture”) to a short foray into fine art (“but making a career out of that would’ve been difficult”) and then to the sales floor of Beams, a Japanese menswear mainstay.

Having developed an interest in buying during his time at Beams, Mr Kamoshita left in 1989 to cofound United Arrows with two friends, Messrs Hirofumi Kurino and Osamu Shigematsu. In the four decades since, they’ve grown the brand from a single store in Tokyo’s teen heartland, Shibuya, into arguably Japan’s leading can’t-go-wrong purveyor of on- and off-duty attire, with  dozens of sub-brands and stores spread nationwide.

The name United Arrows was chosen to represent a shared goal and aesthetic – a number of arrows coming together to hit the same target. On the drizzly morning MR PORTER visits the company’s headquarters in Tokyo’s upscale Aoyama district, this all becomes a little less abstract. We can tell we’re getting close when the sea of drab black suits and clear umbrellas makes way for men sporting Breton-stripe T-shirts, window-pane-check tailoring, selvedge denim and sorry-only-available-in-Japan New Balance. And they are all heading to exactly the same place as MR PORTER.

When we get inside and meet Mr Kamoshita, he explains how the Ivy League look remains his key inspiration. “Ivy League style is something spiritual to me,” he says. “People who adhere to it never look elsewhere. For example, never blue jeans. Never Converse. Only [Sperry] Top-Siders. And only white jeans.”

Spending a week with Mr Kamoshita quickly reveals he has a few other style principles (not mottos – he says they’re “too restrictive” for the role of a forward-thinking creative director) to uphold. This includes never wearing a T-shirt under a shirt. “Not cool.”

But you will also find him to be one of Tokyo’s most unstuffy and jovial men of influence. He’s famously well dressed, but easy-going, and with a distinct essence of the Shitamachi local boy done good. In more familiar terms, he’s a lot more Sir Michael Caine than Mayfair man. Over the course of the week, he offered us a well-informed take on the annals of Japanese style history while guiding us through his enviably stylish world.

“This is my home in Edogawa, in east Tokyo. The style is a mix of mid-20th-century Western with Japanese traditions. I styled the interior so that I’m surrounded by beautiful objects. In such an environment, there’s a type of tension that influences the way you think and live. I might be at home, where I try to relax as much as I can, but I never want to appear rough. I received the shodo calligraphy art from my father. It’s important for that reason, but I don’t know what it says.”

“I love double-breasted jackets. Even when it’s casual and worn at home, as with this knitted version. A double-breasted jacket offers a point of difference from how most people dress. My house is basically out in the sticks. My parents and my wife’s parents lived nearby, which meant I had no choice but to move here. There’s no particular reason I chose the area, other than that. In my spare time, I like to play golf – but my handicap will remain a secret to you.”

“The Asakusa district is where I grew up. It’s a historic place and there are so many good Japanese places to eat, as well as French and Italian. The Japanese way of dressing is similar to the way Italians dress: considered yet conservative. There is no class system in Japan, which affords guys who consider themselves dandies a little more freedom. From a young age, the Ivy League informed my look – I don’t wear socks with penny loafers.”

“This is the United Arrows atelier and archive in central Tokyo. It houses fabrics, old magazines and books. Fashion now is taking inspiration from the 1950s – the fabrics, the colours and the designs – and I choose mine from this room and reconstruct styles of old for Camoshita. I’m wearing tailoring here, but I don’t every day. I do usually wear a jacket, though, either with a tie or not. My key item is a grey flannel suit. That may be a little boring, but it’s an important look.”

“This is the UA Bar in Gaienmae, Tokyo’s unofficial fashion district, and it’s my favourite place in the city. The colours of my outfit and the open collar on my shirt have a very mid-20th-century feel – reminiscent of the French Riviera, Havana or California. My favourite drink at the UA Bar is the spicy mojito.”