When you weave together cotton warp yarn and white cotton filling yarn you get a 90 degree diagonally interwoven pattern called twill. But that’s not where it ends. Given the intricacies of denim fabric and how it is used in construction, which direction the yarns are woven is incredibly important and not to be overlooked. Not only does it play a pivotal role in the how soft the denim will feel, but it also impacts how the wear patterns will look and wear over time.
As it’s such an important component of raw denim, we succinctly walk through the three main types – Right Hand Twill, Left Hand Twill, and Broken Twill.
Right Hand Twill
Right hand twill (RHT) is the most common and can be easily identified by the diagonal pattern that moves from the bottom left of the fabric to the top right. This style was made also famous by Levi’s and has become the industry standard amongst many denim producers.
Right hand twill, or “Z-twill”, has a flatter and smoother surface than the other types of twill. One differentiating characteristic is how much tighter and compact the RHT is due to being woven with S-twist yarn; which is spun counterclockwise, and creates more defined fades.
Left Hand Twill
Conversely, Left hand twill (LHT) or “S-twill”, is woven in the exact opposite direction as RHT, starting from the bottom right and moving up to the top left of the fabric.
Denim powerhouse, Lee, originally used LHT, which has an even softer feel than right hand twill because it is woven with Z-twist yarn, which is spun clockwise. If a left hand twill denim is worn heavily over a period of time, the end results typically carry fuzzy, vertical fading.
As of the last of the three twills, when you combine RHT with LFT, you get the memorable broken twill. First used by Wrangler in 1964, broken twill alternates left and right at every two warp ends to create a peculiar zig-zag pattern.
The premise behind this twill was that it would help combat twisting after washing denim present with right hand or left hand twill; after the denim is washed it tends to twist due to tension of the fabric.