This high quality is known as the "No-La" or Nine-Line Na'In referring to the fine weave.
Halfway between Yazd and Isfahan, and down the road apiece from Kashan lies Nain atop a dry plateau. Peopled by conservative introverts good at reproducing the same small design pool in a limited colour range, the Nain has become the most talked about Persian Carpet in the suburbs of the west.
Although there was some traditional weaving, indistinguishable from Isfahan, the modern Na'In is an example of 1960's western tastes.
It has since become a major rug type, copied across Iran and elsewhere.