The origin and evolution
of a new genre of summer coolness

In Japan, the summer knit fashion genre came into being in 1959. In the more than half a century since then, Yonetomi has continued to spearhead the evolution and creation of this new concept of summer coolness from its headquarters in Yamagata prefecture.


It all began with one man’s vision
and his quest to create something new

In a November 20, 1984 article in a local Yamagata newspaper, Yonetomi Seni founder Ryoichi Oe discusses the time he first conceived the idea of the summer sweater.

“I wondered whether there were lightweight and breathable summer sweaters which could stand up to repeated washings. ( . . . ) I thought about the possibility of unravelling fresco fabric, a material traditionally used for summer suits, to create a yarn suitable for making sweaters, and I commissioned Yamagata Technical High School to do this for me. ( . . . ) After many additional experiments and improvements in the company laboratory, we came up with our first summer sweater prototypes.”

Taking inspiration from loosely woven, porous textiles and airy, dry plain-weave fabrics, Yonetomi continued to develop materials which could help to overturn the conventional wisdom that knits could not be worn in summer. By using synthetic fibers such as Cashmilon™ (acrylic) and Illumiyarn (rayon) to make high-twist yarn, the company succeeded in creating materials with a distinctively crisp texture, turning the idea of summer knits into a reality.

Yonetomi actively shared the original production methods and expertise it used to create these new summer knits with other members of the industry. As chairman of the Yamagata Prefectural Knitwear Industry Association, Ryoichi believed that individual businesses were an intrinsic part of the postwar rebuilding effort in Yamagata prefecture, and he was determined to promote Yamagata’s knitwear industry as a whole. In January 1961, during the coldest part of the winter, representatives from wholesalers, businesses and department stores across Japan were invited to the first-ever summer knit exhibition held at Kaminoyama Onsen Ryokan, a local Yamagata inn, and Yamagata’s new summer knits found themselves greeted with wide acclaim.

The emergence and ensuing popularity of summer knits emphatically overturned the notion that knits were not suitable for summer. In addition, the production of these knits helped to stabilize factory operating rates and management at knitwear corporations, boosting knitwear-related businesses and production areas in Yamagata prefecture and throughout Japan, and contributing to the growth of the industry as a whole. The achievements of Asako Taruishi, then the head of Yonetomi’s summer knit development department, were also recognized with an award from Japan’s Science and Technology Agency.

Yamagata Shimbun, March 14, 1969. Photo provided by Yamagata Shimbun.
Yamagata Shimbun, November 20, 1984. Photo provided by Yamagata Shimbun.


Our pursuit of the “ideal” materials fuels a never-ending evolution

Yonetomi’s summer knits encapsulate a story of invention and evolution. The spirit which animated our quest for the most ideal materials lives on today, with original spinning and plying methods developed just for these summer knits. We look for ways to make the most of materials including cotton, silk and synthetic fibers such as polyester, and we knit high-twist yarns at the tightest possible tension to create fabrics with a dry surface feel that one would not typically expect from such materials. Ever cooler, ever breezier, and more easily washable, the evolution continues.

These summer knits can be easily cared for at home, and their casual designs make them perfect for everyday use. But while they can be worn as comfortably as an ordinary t-shirt, you can see and feel the quality that sets them apart and makes them special. From our Yonetomi headquarters in Yamagata prefecture, our summer knit story continues, one sweater at a time.