Thermal shirts are a staple for colder seasons, but many people have experienced the fabric stretching and losing its shape over time. Repeated wear and washing often cause the knit to loosen, distorting the silhouette. To improve this common issue, WASEW worked with skilled knitters in Wakayama on a new approach. The “GENKOTSU THERMAL” introduced here is the result — an innovative thermal shirt designed to resist losing its shape.
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The Biggest Drawback of Thermal Shirts
・The Structure of Waffle Fabric -
Overcoming the Drawback
・A Project with Skilled Knitters in Wakayama -
Waffle Fabric Knitted on a Vintage Machine
・The Low-Speed Rib Machine Known as the “Genkotsu Machine” -
A Thermal Shirt That Resists Losing Its Shape
・A Fusion of Traditional Technique and Modern Ideas
1. The Biggest Drawback of Thermal Shirts
The Structure of Waffle Fabric
The biggest drawback of thermal shirts is their tendency to lose shape.
The reason lies in the structure of waffle fabric, which is used in many thermal shirts. Its uneven, three-dimensional knit creates excellent insulation, but at the same time, its elasticity makes it prone to stretching and loosening through repeated washing. As a result, the silhouette gradually changes and begins to look worn out — though some may see that as part of its charm.
2. Overcoming the Drawback
A Project with Long-Established Knitters in Wakayama
To address the biggest issue of thermal shirts, WASEW launched a project together with experienced knitters in Wakayama. By drawing on their knowledge and technical skill, the team went through repeated trial and error to develop a waffle fabric that would better resist losing its shape. The result was a fabric that remains soft while holding its silhouette even through long-term wear.
3. Waffle Fabric Knitted on a Vintage Machine
The Low-Speed Rib Machine Known as the “Genkotsu Machine”
The “GENKOTSU THERMAL” born from this project is knitted on a vintage low-speed rib machine known as the “Genkotsu Machine.” This is the same type of machine used to knit ribs for sweatshirt hems and cuffs, and for T-shirt necklines, and it gives the fabric its soft feel.
But using the machine alone was not enough. To create a waffle fabric that resists losing its shape, the craftsmen customized the machine itself — adjusting the gauge, the winding speed, and the tension in fine detail. These adjustments made it possible to retain softness while improving stability.
The fabric is also finished in tubular form and packed carefully in a folded state, so that twisting is minimized even before sewing begins.
4. A Thermal Shirt That Resists Losing Its Shape
A Fusion of Traditional Technique and Modern Ideas
WASEW’s “GENKOTSU THERMAL” is a thermal shirt created through the fusion of old technique and modern ideas.
By specially adjusting the “Genkotsu Machine,” which dates back to the same era as loopwheel knitting machines, WASEW achieved both a soft texture and durability that resists losing shape. The fabric is finished in tubular form and carefully folded for packaging, ensuring that twisting is minimized even before the sewing stage.
This shirt brings together Wakayama craftsmanship, traditional machinery, and modern know-how in a way not found in ordinary vintage thermals. We hope you will experience the “GENKOTSU THERMAL” for yourself and enjoy the way it maintains its silhouette over time.
