Denim jeans are one of the most iconic, ubiquitous and universally loved items of clothing ever produced. Do you remember the first pair you ever wore? Have you ever considered how many pairs you’ve owned in your lifetime? While we live in a world where fashions are changing faster than ever, denim jeans continue to maintain a constant presence. In Spring 2017, Tokyo brand WESTOVERALLS was born. Not to make jeans for the discerning connoisseur, but to deliver quality denim to anyone who simply likes to look good.
Tassei Onuki has been involved with a number of brands as a designer, and his popularity is ever-rising. From tailoring to American and European casual wear, he’s well versed in an array of styles. However, his first love is vintage fashion and that remains to this day.

“I started working at a vintage clothes store when I was 18, and I was working as a buyer until I was 29. I suppose I’ve just always loved “things”… I recall I already knew what “jeans” meant when I was 3 or 4, and I guess it was my entry point into fashion. When I was in elementary school, I’d save up my allowance and would go buy the Levi’s® “Big E”… I was always a bit of a show-off and ever since I was little I was trying to look good hahaha”.

By junior high school he was already saying that he wanted to be a fashion designer. This was still a dream at that time of course, and he never received any formal education or training to fulfill it. It was through his experiences at the vintage clothing store that he learned his craft. It was those experiences that lay the foundations for his growth as a designer.

“By 19 they left me to manage the store and would send me on buying missions… All the vintage stores back then only stocked American stuff, so I decided to go to Europe. I visited Portobello Road in London, looking at hand-made jackets… and the first time I went to France I was taken to a big warehouse full of vintage threads in Normandy… it was like nothing I’d seen before. It just blew my mind. Martin Margiela also happened to be there at the same warehouse when I visited… it was that kind of place.”

With these rich experiences, Tassei returned to Japan and started designing his own items using dead stock and fabrics from the vintage clothes store he was working at. Ever since then, vintage clothes and creating new fashion have been inseparable to him. After a period working as a freelancer, Tassei went on to set up WESTOVERALLS.

The first collection was centered on five types of jeans made from vintage denim, along with trucker jackets and other wearable items and accessories. Simple and compact. Knowing Tassei’s background and experience, his first collection was surprisingly minimal.


“Everyone loves denim, but everyone loves it for different reasons. I love denim for a myriad of reasons. I’m happy if a hardcore denim and vintage lover likes my designs, but I didn’t just want to design for that mindset. I wanted my designs to look great on and be appreciated by a broader customer. That thought was distilled down to those five designs. I went for a baggy silhouette without being oversized.”

These five designs continue to be central to his range and are offered in sizes 26, 28, 30, 32 and 34 inches. He plans to include 24 inches in forthcoming ranges for the slimmer woman.

The trucker jackets on the other hand, indicate their sizes by letter, in ways we haven’t seen before. (ex. Size “A”, Size “F” etc…)

“This is an homage to the 501 vintage Big E which had types A, S and F. My trucker jackets go from the smallest“A” to“S” and“F”. It’s basically a simple S, M, L expressed in different letters. The reason why I chose not to go with S,M,L is because I want customers to not feel limited by their own “size”. Meaning that, for someone who is a size “S” wouldn’t generally go for an “L” just because it’s “not for them”…but who’s to say that? Why limit yourself? Also, it’s not just the size that differs, the cuts and overall shape differ somewhat too between A, S and F. With the jackets, I maintain a bit of distance between the buttons at the end of sleeve, so that even with women wearing the “S” can have an overall well-balanced silhouette, and making it easier to coordinate with other clothes”.

He wants his clothes to fit as many people as possible while offering them freedom to choose what they want. The five jeans cuts include flared, straight and tapered, but the brand purposefully does not label them as such.

“It’s along the same principles as the size, I just separate it according to how the silhouette looks according to the wearer. Something might look like a straight cut if I wear it… then for me, that pair of jeans is a straight cut. I just like to keep things as simple as possible for the customers”.


Tassei also focuses on the rubber waist interlining. It looks great and is arranged in a really attractive, modern way, making it somewhat of an key characteristic in the overall construction of his jeans. However, Tassei tell us that he was inspired by a particular denim brands’ silhouette from the 1950’s.

“Having the interlining really lets it fit around your waist. It also prevents color transfer when you tuck in your shirt, even with dark denim”.

The 13.5oz denim is produced by manufacturers in Ihara-city, Okayama and has a vintage-like sheen and color about it. Add to this the rubber waist interlining and it’s really something special, just waiting to be worn. In the first season, Tassei produced rigid, one wash and bio wash denims, in a combination of five colors including ice blue and black for each product model. The majority of black denim lately uses back thread for both warp and weft, however for WESTOVERALLS Tassei chose the old-fashioned weave of black warp and white weft.


“There was a time where new knowledge was the be-all and end-all for me… but once I started making my own clothes and I developed a customer base who’d interact with my creations I naturally lost those urges of just pursuing “new” stuff or showcasing my “knowledge.” I think I feel satisfied that my “things” are being sent out to the wider world and getting out there. And that is enough for me. I have nothing else to prove”

The thread used to make the denim looks like usual cotton thread, but actually has a polyester core, for maximum durability, and is known as a core yarn. The fabric is woven using the latest technology and offers a tightly packed high-class finish, which is highly resistant to wear and tear. Tassei has actively moved away from the holy-grail for denim lovers, the selvedge, because he believes that the edges of the fabric affect the silhouette when worn.

Tassei is convinced that anyone who comes across his jeans will want to try them on, and once they do they’ll be in it for the long haul together.


Pouch constructed from raw 13.5 oz black denim.
Wide rubber suspenders.

Back in the 1800’s when belts weren’t common place, woodcutters wore overalls with bibs. The inconvenience and discomfort of this apparel drove forth its evolution. The bib was removed at the hip and would go on to become the jeans as we know it today. These stories are what inspired the vintage-loving Tassei to dedicate his life to fashion. What new innovations can he bring to the game? What new standards that the whole world can enjoy will he be able to create?

“I want the vintage clothes hunters of the future to speak about us… “What?! You got some WESTOVERALLS in!?” That kind of thing, you know what I mean?”



Tassei Onuki

Born Nov 17, 1980. Interested in vintage clothes since his elementary school days, he worked as a buyer sourcing vintage wear from the US, the UK and France for more than a decade. In 2010 he set up his own brand MANUFACTURED BY SAILOR'S (Marine themed bags and accessories) while also working on project direction for select shops and design companies.
He’s currently creative advisor to HELLY HANSEN in a freelance capacity, while also carrying out project direction for HELLY HANSEN R.M.C, OLDMAN’S TAILOR and WESTOVERALLS.

PHOTO : Yohei Miyamoto
TEXT : Rui Konno