When designing a "thin wallet," the biggest hurdle, along with the structure, is the thickness of the material. A typical wallet often uses 1.0mm to 1.5mm of leather, but if you simply stack and sew these together, the thickness will be 1cm to 2cm or more.
One standard we arrived at when producing compact wallets like Tenuis 3rd and 4th generation, Tynd, etc. is to thin goat leather to 0.5mm. Anything thicker than this loses softness, and anything thinner affects strength, so we use 0.5mm as the standard. The cowhide on the exterior has different characteristics from goat leather and is used for different purposes, so the standard is 0.8mm. This also achieves softness and thinness while maintaining strength and texture. It may not sound like a large number, but every 0.1mm makes a big difference in properties.
The Tenuis all-cowhide version pursues a different direction from the goat leather version, with a different standard of 0.8 mm on the inside and 1.4 mm on the outside. This model does not utilize the elasticity of goat leather to insert cards, but instead uses taut cowhide to design three-dimensional card slots.
To make these, it is not easy, as the edges of the material, called the koba and hem, must be carefully overlapped and pasted without any deviation, and there are even some parts where the already sewn parts must be bent and avoided while sewing. This is a very time-consuming and labor-intensive task, so much so that it is avoided in factories, even for craftsmen who are not used to it.
Simply preparing thin materials and sewing them together doesn't require much skill. However, these wallets are packed with the culmination of over 10 years of trial and error spent trying to determine the perfect boundary between these two, while retaining the characteristics and texture of Italian leather and goat leather, ensuring the functionality they are designed to provide, and being durable enough to withstand rigorous daily use.
Tenuis 4th generation
https://solahanpu.com/products/tenuis-fourth
Tenuis 3rd generation
https://solahanpu.com/products/tenuis-third
Tenuis all-leather version
https://solahanpu.com/products/tenuis-bg