Hummm...I've have a water bed and use king sized cotton sheets (California King) and they hold their size (as they have to be tucked into the corners by pockets built into them.

I'm using Egyptian cotton sheets now but I've used just plain cotton ones before. I also wash in hot water, no shrinking.

Is your bed really thick? Maybe you need sheets designed for really thick beds.

Don, have you ever thought about looking on eBay for a vintage linen one? It would probably cost a mint, but will last forever.

Also do you buy king or california king?...arnt cali kings bigger?

California Kings and four inches different on each side. Most blankets seem listed to fit both types. The sheets fit fine. My Amazon flannel sheets would fit a considerably deeper mattress. (I highly recommend the Amazon Pinzon flannel sheets for value. I have owned many brands)

I like linen blankets, but I'm not sure I want to spend $600. It seems to me that a variety of different king blankets from Macy's shouldn't be 18" too narrow to tuck under the mattress. I also have an Eddie Bauer 100% wool blanket that isn't close to being wide enough to tuck in. I'm perplexed. I've even rechecked orders to make sure I order the right size.

I also noticed that blanket size seems smaller these days, as if everyone uses a bed skirt and won't notice.

Don, you might try a blanket-type bedspread. They're a LOT bigger and can easily be tucked under the mattress. Usually cotton; sometimes with fringe.

And if you have a cat it can be used as a cat toy also..haha.

It has been many years since I have had a blanket that tucks under the top mattress, the trend has been comforters which do not tuck in at all I would try LLBean's home section.

I have the same problem. All my blankets shrink within a couple of years of use. Now the ones I bought for my king are on my queen beds.