Why is the herringbone weave pattern of the cloth historically important?
The weave pattern of the Shroud is three-hop (or three-over-one) twill, very distinctive and rare. What this means is that the weft or cross thread passes over three warp threads, under one, over three, and so forth for each run of a weft thread across the loom. The next weft is offset by one, and the next one, and the next one. That is twill. What makes it herringbone is that after a few threads the offset is reversed, and then reversed again after a few threads. We can clearly see the twill pattern in the fourth, fifth and sixth threads from the top.
Warp threads are the threads that are strung onto the loom before weaving begins, usually in a vertical direction. They run the length of the cloth.
Weft threads are the threads that run across, being passed over and under to create the cloth. Twill means the cloth’s pattern has a diagonal wale or texture. Denim, as used in ordinary blue jeans is an example of twill.
Herringbone simply means the offset (twilling) is periodically reversed, hence the diagonal wale is reversed. The resulting appearance is that of a herring fish bone. Other decorative and complex patterns including lozenges, waves and zigzags can be created in twill weaving by varying the hop in different ways.
The weave is particularly important because it is evident in one of the illustrations in the Hungarian Pray Manuscript.