The complete guide
How to Choose a King Size Silk Pillowcase
The problem with most pillowcases
Most of us never think about the pillowcase. We buy sheets, and whatever case comes in the set goes on the pillow. Cotton is fine. It is also rough, at a microscopic level, and it holds onto moisture. If you have long hair, you already know what cotton does overnight. You wake up and half your hair is going one direction and the rest is going somewhere else.
Silk behaves differently because the fibre is smoother and the weave sits flatter. There is simply less for hair and skin to catch on. That is a property of the fabric, nothing more dramatic than that, but it is the reason silk pillowcases went from a niche item to something you now see in regular bedding aisles.
The second problem is fit. King pillows are long. A lot of silk cases sold online are cut to standard or queen dimensions and then described loosely, which leaves a king pillow either jammed in or rattling around. This one is cut to 20 x 36 inches (51 x 91 cm), the proper Canadian king measurement.
What momme actually tells you
Silk is sold by momme, written as mm in some listings, and it is the single most useful number on the label. It measures weight, and weight tells you roughly how much silk is in the fabric. Higher momme means denser, more substantial cloth.
For bedding you will mostly see 16, 19, 21, 22 and 25 momme. Sixteen is light and inexpensive, and it feels lovely in the shop but tends to show wear at the seams sooner. Twenty-five is heavy, luxurious and priced accordingly. Twenty-one sits in the middle and is where a lot of people land once they have tried a couple. It has enough body to drape over a pillow properly, it does not feel flimsy, and it can take regular gentle washing without going thin.
This pillowcase is 21 momme. The maker also lists a 600 thread count and grades the silk 6A. Thread count is a less meaningful measure for silk than it is for cotton, because silk filaments are so fine, but 6A is worth noting. Silk grading describes the raw filament, with 6A at the top of the usual scale, meaning long and even fibres with fewer joins in the yarn. Evener yarn gives you a smoother, more consistent surface.
Both sides matter
Here is a detail that separates a good silk pillowcase from a disappointing one. Many cheaper cases use silk only on the sleeping face and back it with cotton or polyester. It cuts the cost significantly. It also means that every time you flip the pillow over in the night, you land on the cheap side.
This case is 100% mulberry silk on both faces. Mulberry silk comes from silkworms raised on a mulberry leaf diet, which produces a long, uniform filament. It is the fibre used for fine silk clothing and for most of the better bedding. When people search for the best pure silk pillowcase, this double-sided construction is usually what they are actually after, even if they have not put it in those words.
Closures, and why zips win on a king
You get two common closures on silk pillowcases. An envelope flap folds the extra fabric over the pillow end. A zipper closes the opening completely.
On a standard pillow, an envelope flap is usually fine. On a king pillow, which is a full 36 inches long, it is more of a gamble. The pillow shifts through the night, the flap works loose, and you wake up with a bare corner sticking out. A hidden zipper, like the one on this case, holds everything in place from lights out to morning. It also keeps the edge looking crisp when the bed is made.
Two small habits help the zip last. Close it fully before you wash the case, so the teeth cannot catch the silk. And do not force it when the pillow is overstuffed, ease the fabric along instead.
Who this suits
Anyone with a king bed and king pillows, first of all, since the fit is cut for exactly that. Beyond that, it tends to appeal to people with longer hair who are tired of morning tangles, people who find cotton too warm against the face, and anyone who wants one upgrade to the bedroom that is noticeable without redecorating.
The blue grey colour is deliberately quiet. It is cool-leaning, more grey than blue in daylight, and it works against white, cream, charcoal and navy. If your bedroom is already busy with pattern, a solid tone like this calms it down. If your bedroom is all neutrals, it adds a bit of depth without introducing a new colour story.
It also makes a reasonable gift. A silk pillowcase sits in that useful category of things people enjoy but rarely buy for themselves, and a neutral colour removes the guesswork.
Caring for it so it lasts
Silk is a protein fibre, closer to hair than to cotton, and it wants the same gentle treatment. The care guidance here is a gentle hand wash or dry clean, no bleach.
For a home wash, fill a basin with cool water and add a small amount of detergent made for delicates or wool. Swirl the case through the water for a minute or two. Do not scrub it, and do not leave it soaking for ages. Rinse in clean cool water until the water runs clear.
Then the important part. Never wring silk. Press the water out between your palms, lay the case flat on a towel, roll the towel up and press gently to draw out the rest. Hang it to dry in the shade, or dry it flat. Direct sun and radiator heat are the two things most likely to dull the colour and stiffen the fabric.
If it needs pressing, use the coolest iron setting on the reverse side while the silk is still a little damp. Most of the time you will not need to bother, because silk hung to dry drops its own creases.
Washing every one to two weeks suits most people. If you use heavy night creams or leave-in hair products, go more often. Having a second case means you always have one clean while the other dries, which is the real reason most people end up buying a pair.
A few things to check before you order
Measure your pillow. This sounds obvious, but pillow sizing is where most silk pillowcase returns come from. In Canada, standard pillows run 20 x 26 inches, queen 20 x 30, and king 20 x 36. If yours measures 36 inches long, this is your case.
Check how many you need. One pillowcase comes per pack, so a king bed with two pillows needs two orders of this item.
And think about where the zip will sit. Most people put the zipper end toward the outside edge of the bed, away from the middle of the mattress, which keeps it well clear of your face.
The short version
This is a king size silk pillowcase, 20 x 36 inches (51 x 91 cm), made from 100% mulberry silk on both sides at 21 momme and graded 6A. It closes with a hidden zipper and comes in a solid blue grey. One case per pack.
The silk weight is substantial enough to drape and last, the double-sided construction means there is no cheap back to roll onto, and the zip keeps a long king pillow where it belongs. Wash it gently in cool water, keep it out of the sun, and it will stay good for years.