Cordovan

Cordovan is not leather in the common sense of the word. It is a fibrous, compact layer that sits beneath the skin on the hindquarters of a horse: two ovals per animal, each roughly the size of two open palms. It is called shell because the tanning process brings it out that way — dense and closed, without the grain that normal leather has. That is why it has no grain to show: the surface is smooth, almost glassy, and catches light like nothing else.

The tanning is vegetable and slow: a good six months between the vat, fat liquoring, and hand finishing, with the surface roller-glazed until it becomes that deep, lustrous sheet you recognise at a glance. Very few people in the world do it well: Horween in Chicago, who turned colour #8 — that dark bordeaux — into a proper name, and Shinki Hikaku in Japan, drier and tauter. The cost comes from exactly this: two ovals per horse, half a year of work, high wastage.

On the wrist it behaves in its own way. It is stiff for the first few days, then it settles and does not go back. It does not crack: where calfskin creases, Cordovan forms a soft wave that is barely visible. Rain will mark it — small pale bubbles that are alarming the first time — but a horsehair brush brings them back in. In twenty years of making straps I have seen very few actually wear out: they change colour, darken where the cuff rubs, and they last.

I cut it at 1.4 millimetres thick for flat straps, which is the right approach for this material: padding takes away its character. It suits watches that have a history to carry — a Speedmaster, a Reverso, a 1960s chronograph — and works well with dark or cream dials. It pairs less naturally with polished steel than alligator does; with brushed steel and rose gold it is at home.

It needs little care, and that little should be done: a soft brush every now and then, no heavy creams (they cloud it), no deliberate water. If it loses its shine, a cloth and the pressure of your hand bring the lustre back. It is a material that rewards those who leave it alone.