What weave is traditionally used for the sturdy denim fabric in classic blue jeans?

Classic denim is traditionally woven as a 3x1 right-hand twill.

In this construction, three warp yarns pass over one weft yarn, producing the diagonal ribs visible on denim. The warp yarns are usually dyed blue with indigo, while the weft yarns are commonly left white, helping create denim’s familiar blue face and lighter interior.

“Right-hand” describes the direction of the diagonal twill line on the fabric. It does not mean that the fabric is intended only for right-handed people. Other denim constructions exist, including left-hand twill and broken twill, but 3x1 right-hand twill became the classic heavy-jeans standard.

Fabric weight, yarn size, dyeing, and finishing also affect how jeans feel and fade. Thus, two pairs made from denim can behave differently even when both use a conventional twill structure.