How to Read a Knot
A high knot count is sold as a score. It is not. Here is what the number actually tells you, and what it hides.
Someone tells you a rug has 400 knots to the inch, and says it like a score. Higher is better. You should be impressed.
Don't be, yet. The number on its own means almost nothing.
A knot count only makes sense inside its own kind of rug. A city rug from Tabriz needs a very high count, because it's drawing thin curling vines and fine medallions, and you can't render a curve without a lot of tiny knots. A Moroccan rug is the opposite. Its shapes are big and blocky, a diamond, a broad stripe, a lozenge the size of your hand. Those don't need hundreds of knots. Pack them in and you'd only blur what makes the rug what it is.
So a coarse Moroccan and a fine Persian aren't a worse rug and a better one. They're answering different questions. One is a bold mark you read across a room. The other is a small painting you lean in to see. Judging them by the same number is like judging a poster and a postage stamp on how much detail each one holds.
There's one more reason not to trust the number: it's often wrong. The count a seller quotes and the count on the actual rug don't always match, and when they differ, they differ in the seller's favour.
So here's the whole skill. Turn the rug over. The back is where the knots live. Count them yourself in one inch, then ask the only question that matters: is this rug fine and detailed, or bold and simple, and does the weaving suit what it's trying to be? A tight, even back on a fine rug is good work. An honest, chunky back on a bold Moroccan is also good work. The number was never the point. The rug was.