1. Which Knitted Fabrics Unravel and Which Hold Together?
If a small hole appears in stockings or socks, a vertical line can run from it. This "laddering" does not happen in all knitted items. According to encyclopedias, unraveling when a thread is cut is a characteristic of weft knitting. Warp knits, such as tricot and milanese, are resistant to laddering and are often used for underwear [3]. Japanese dictionaries also explain that tricot is less prone to fraying compared to weft-knitted jersey [4]. Even with the same yarn, the way it is knitted changes how it unravels. So, what is different about the knitting method that unravels easily?
2. Why Weft Knitting Made from One Thread Unravels Easily
Imagine a hand-knitted sweater. A single yarn moves sideways, creating loops to finish one row, then moves to the next. Weft knitting (yokoami) works this way: one thread creates one row [3]. In this structure, if one thread breaks, the loops connected by that thread can easily come undone together. Pulling the thread end can cause loops to pop out one after another. This matches the flaw described in dictionaries, based on general reference materials. So, how does warp knitting avoid this problem?
3. How Warp Knitting Uses Many Threads at Once
Warp knitting uses machines that arrange many threads and knit them simultaneously, feeding them along the length of the fabric (parallel to the edges) [1]. Each needle receives a separate thread, and all threads are knitted at the same time [2]. Strictly speaking, some explanations note that it knits in vertical columns rather than rows [2]. As a result, the loops in one row are made from many separate threads [1]. Each thread zigzags along the length of the fabric [1]. This may mean there are fewer loops connected only by that thread. This may be one reason why unraveling does not spread easily. This explanation is based on general English-language descriptions. So one thread does not hold the whole row together by itself.
4. What Warp Knit Fabrics Like Tricot Feel Like in Underwear
The surface of tricot has fine vertical ridges, and the back has horizontal ridges [1]. The texture is soft, and it easily creates a drape (a soft, naturally hanging shape). It stretches slightly in the vertical direction but hardly at all in the horizontal direction [1]. Warp knit fabrics are divided into three main types: tricot, milanese, and raschel, all of which are said to be relatively resistant to laddering [2]. Double tricot, which uses two guide bars, has a substantial fabric that resists unraveling and has many uses, according to the World Encyclopedia [4]. Being soft and resistant to unraveling may be why these fabrics are chosen for underwear. Is there a scientific attempt to organize how unraveling spreads?
5. How Researchers Used Mathematics to Classify the Spread of Unraveling
On July 14, 2026, researchers from Ritsumeikan University, Tohoku University, and Aoyama Gakuin University published a paper in the physics journal Physical Review X [5]. Titled "Topological Defect Propagation to Classify Knitted Fabrics," the study uses knot theory to classify knitting based on how defects spread through the fabric [5]. Here, "defect" is a research term for a locally undone state of a stitch unit, not a reproduction of actual thread breaks or laddering. An American Physical Society commentary notes that in the knitting methods studied, if defects connect in a continuous line across the fabric, it unravels completely [7]. Where does warp knitting fit in this classification? This paper deals with general knitting classification, and its relationship to warp knitting (tricot) cannot be determined from the available materials.
6. How New Knitting Structures Could Stop Unraveling from Spreading
According to Ritsumeikan University, this research proposes examples of new knitting structures where defects do not spread easily, preventing chain-reaction failure even if partial unraveling occurs [6]. The Japan Science and Technology Agency (JST) Science Portal reported that new stocking knitting methods resistant to laddering have been devised [8]. However, specific numbers in that report (differences in unraveling between old and new methods) could not be verified in the press release or paper text, so they are not included here. Warp knitting is already widely used in products as an unravel-resistant method. This research aims to organize unraveling theory to design even stronger knitting structures.
Try It Yourself
Check the tags on your clothes to see the material (knitting method is often not listed). As a separate activity, look inside underwear or socks with a magnifying glass to see if you can find fine vertical ridges. Some clothes cannot be distinguished this way. Do not cut with scissors or pull threads forcefully. At a clothing store, compare clothes with different stretch properties. Gently stretch them vertically and horizontally to feel the difference. You can read a summary of the research in the Ritsumeikan University news (in Japanese) [6].