If you've shopped enough jiu jitsu gis, you've probably asked yourself: What is all this "weave" nonsense about? What is the difference?
Well, we've broken it down for you...
GSM = Weight
Almost all jiu jitsu gi companies will identify the GSM of the fabric. This stands for "grams per square meter" and is the weight of the fabric used. Most gis range between 375 GSM and 890 GSM, with some outliers on either end. You'll typically see the lower range featured as Single Weave or Pearl Weave, the mid-ranges as Pearl Weaves or Gold Weaves, and the heavier end of the spectrum as Double Weaves.
Unfortunately, there's no official naming standard in the gi market, and some gi companies will simply use Pearl, Gold, and Double, as it directly correlates to the fabric's weight.
Weave = Appearance
However, you may have noticed that the fabric on some gis look a little different. That's because there is actually a difference in weaves. This has to do with the manner in which the "weft" is woven through the "warp." The warp refers to the set of threads, aligned parallel to each other, that are stretched on the loom first, before the weft is woven through.
A single weave, logically, entails one set of warp, with weft woven through. In the gi world, a single weave usually is the simplest version of this, with weft crossing over one warp thread and under another. This leaves a smooth, flat appearance to the fabric. Notably, under this definition, pearl and gold weaves are also technically single weave fabrics. However, what differentiates them is how the weft is woven.
As its name implies, the pearl weave has the appearance of multiple strings of pearls aligned together. This happens when a looser, wider weft is alternated with a thinner, tighter weft. The looser weft creates the appearance of raised pearl-looking bumps. The Pearl Weave Plus is similar, but the looser weft is woven at a slight diagonal, giving a flattened rope appearance. Pearl weaves are the most common fabrics used for gi jackets.
A gold weave has a distinct ladder appearance, created when wider, heavier warp threads are interspersed between thinner warp threads, and the looser weft is woven over an entire section of the thinner warp threads, before weaving through another section, then jumping back over again. Similarly, a honey comb weave also features weft jumping across several rows of warp threads, but without the delineating heavy warp threads, the a more hexagonal "honey comb" shape is left in the areas where the weft weaves tightly through warp.
A true double weave fabric is when two or more sets of warps and one or more sets of weft are woven together, essentially creating a double layered fabric. Because significantly more threads occupy the same square meter space, the fabric is therefore much heavier.
"Better" is all personal preference. Sorry guys and gals, we don't have the magic answer for you on that.
Some people like lighter gis, some heavier. Some people feel a double weave is harder for their opponent to maintain grips. Some claim the gold weave shrinks more than the others. Some people think the heavier the gi, the more durable it is and the longer it lasts. This last claim does appear to have anecdotal support, but the longevity of your gi is affected more by its use and care than by its weave.
When it comes to gis and their weaves, there are only two things that really matter: heavy versus light (or something in between), and how you like the feel and look of the fabric.