Anglage is the beveling of sharp edges on plates, bridges, and other components of a caliber: it's not decoration added on top, it's the metal itself that changes form. It's created with a file and burnisher, by hand, tilting the tool at roughly 45 degrees across the component's edge and maintaining that line consistently along the entire length of the edge. It sounds simple. It isn't.
I saw the difference at the bench even during my years at Piaget: machine-executed anglage or work done with rotary tools leaves a rounded profile, slightly matte, that doesn't change under artificial light. Hand-work with a burnisher on blued steel or German silver produces a flat bevel, with two surfaces meeting in a precise line — and that line catches light like a taut wire. That's the point: not the width of the bevel, but the sharpness of the edges that define it.
The most demanding version is mirror-polished anglage on internal angles, those recessed corners, where the file won't reach and you work with wooden slivers loaded with diamond paste. On certain calibers — the source mentions over 1,300 internal angles on a minute repeater — a single watchmaker can spend weeks on this operation alone. On the KV21 caliber, the German silver bridges show wide, mirror-polished bevels with corrected internal angles: it's a declared aesthetic choice, almost ostentatious, that reveals how much time was invested in the piece.
Anglage exists in contrast with other surface finishes: Côtes de Genève, perlage, circular graining, soleiillage are all textures applied to the flat faces of the component. Anglage concerns only the edges. This technical distinction is often confused, even in catalogs. Black polishing, by contrast, is mirror-polishing of flat surfaces — typically on the tails of levers — and has nothing to do with beveling.
In Glashütte movements, anglage is associated with the three-quarter plate tradition and swan-neck adjustments. On Minerva calibers, the effect is heightened by the dark finish of the argentan alloy, which makes every bevel stand out by contrast. In both cases, the sapphire caseback is there for a reason: without visibility, all this work would remain invisible to the owner. But the work is there nonetheless, and this is the measure of a manufacture's seriousness.
