The watch world is full of highly technical, often highly French terms that any normal person, reasonably, doesn’t know. Welcome, then, to Horology in a Hurry, a semi-regular column where we’ll break down these terms at length one at a time to give you a better understanding of how watches work. This week: Guilloche.

What is it?

Guilloche (also called engine-turning) is a decorating technique in which intricate geometric patterns are engraved onto watch parts like dials and cases. Lines are etched into the part via a hand-operated lathe, either in straight lines or in circles. The end result is an eye-popping design that adds value and visual flare to a timepiece. Guilloche patterns themselves come in all sorts of varieties like “hobnail,” “sunburst” and “barleycorn.”

Where did it come from?

The basic technique goes back to the 1500s, when it was used on softer materials like wood and ivory; but in the 1700s the process was applied to metals. By the late 18th century, watchmakers began experimenting with the technique on dials and pocket watch cases. Vacheron Constantin and Abraham-Louis Breguet are among the earliest adopters.

Why does it matter?

Guilloche is considered to be something of a disappearing art — at least when done traditionally by hand from a skilled watchmaker. Though it’s worth noting the same effects have been successfully achieved through simpler (and cheaper) modern processes like CNC machining and stamping. The guilloche patterns themselves aren’t particularly common today (presumably due to consumer tastes for simpler timepieces) but most watches that do incorporate them are classy and eye-catching to say the least.

Who does it best?

Seiko SARB065 “Cocktail Time” $579
One of Seiko’s entry-level mechanical watches, with a radiant sunburst guilloche dial design. Once a Japan-only model, Seiko announced recently that it would add more “Cocktail” models to the lineup and bring them stateside.

RGM 801-EE $10,400
American watchmaker Roland G. Murphy is working to keep hand-operated guilloche alive, and in the 801-EE, the work shows not on the dial but through a skeletonized main plate.

Vacheron Constantin Métiers d’Art Elégance Sartoriale $53,600
Vacheron’s Métiers d’Art Elégance Sartoriale collection puts the watchmaker’s incredible guilloche skills on display with five incredibly intricate dials modeled after fabric patterns.

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