What Is 6A Grade Silk?
6A is the highest grade of raw silk there is — the top of a scale that runs 6A, 5A, 4A and down through the alphabet to the coarse, defect-ridden bottom. It measures the quality of the silk fibre before it's woven: how long, even, clean, strong and pure-white the thread is. Only the finest reeled silk earns it, and it's the grade you want against your skin.
It's also a term that gets printed on a lot of labels, so it's worth knowing what it actually certifies — and what it doesn't.
So what does 6A grade actually mean?
It means the raw silk sits at the very top of the international grading scale. China's national raw-silk standard runs from 6A at the summit down through 5A, 4A, 3A, 2A, A, and then B, C and lower — and only around five to ten per cent of the world's silk is good enough to be classed 6A. To qualify, the reeled thread has to be long, remarkably even in thickness, clean of the little lumps and impurities that mar lesser silk, strong, and a natural pearly white. It is, in short, the silk with the fewest faults.
How is silk actually graded?
On a handful of unforgiving measures — and this is the part that makes the grade mean something. Inspectors assess the raw silk for size deviation, evenness, cleanliness and neatness, among others, and here's the catch: a lot is graded by its weakest result, not its average. Fall short on any single measure and the whole batch drops a grade, no matter how it scored elsewhere. There's no rounding up and no compensating a flaw with a strength, which is why 6A is genuinely hard to reach rather than simply generous.
Is 6A grade the same as momme?
No — and confusing the two is the most common mistake people make. Grade describes the quality of the raw fibre; momme describes the weight of the finished, woven fabric. A silk can be a high grade but woven thin and flimsy, or heavy momme spun from middling fibre. They answer different questions — how good is the thread, and how much of it is in the cloth — and you really want both: top-grade fibre, generously woven. One without the other only tells you half the story.
Does 6A grade actually matter for a pillowcase?
It does, in the quiet ways you feel rather than see. Long, even, clean fibres weave into a smoother, more uniform surface — fewer slubs to catch your hair, a more consistent glide against your skin, and a fabric that resists pilling and lasts through years of washing. Lower-grade silk, with its shorter, less even threads, simply can't hold that finish. For something your face rests on for a third of your life, the grade of the thread is doing more work than you'd think.
How do you know silk is really 6A?
Carefully, and not on the strength of the badge alone. Here's the honest part: "6A" is graded at the raw-silk stage, and there's no certificate stapled to a finished pillowcase to prove it — so the label is, ultimately, the maker's word. Plenty of sellers print "6A" because it sells, not because they've verified it. So treat it as one signal among several rather than a guarantee: look for 6A grade and a stated 22 momme weight, the words "100% mulberry silk", and an OEKO-TEX certification you can actually check. Together, those tell a far more trustworthy story than any one claim on its own.
For the record, our LS Silk NZ pillowcases are 6A-grade, 22-momme, 100% mulberry silk, OEKO-TEX certified — the whole set of signals, not just the flattering one.
Grade is one of those details that sounds like marketing until you understand it, and then quietly becomes the thing you check first. It's the difference between silk that merely looks the part on day one and silk that's still smooth, strong and lustrous years later — the long, faultless thread doing its patient work, night after night.