Skeleton dial

A skeleton dial is a dial that has been pierced, cut away or left out entirely so that the movement underneath can be seen from the front of the watch. It may be a ring carrying the hour markers with an open center, a sapphire disc with printed markers, or nothing at all beyond a chapter ring on the case.

What that reveals is worth thinking about before you buy one, because it is not the side of the movement most people picture. Through an exhibition caseback you see the bridges, the balance and the rotor. Through the dial you see the dial side: the motion work that drives the hands, the keyless work behind the crown, the date ring if there is one, and a large area of flat mainplate. Makers deal with this in three ways. Some open only the center and leave the busy parts covered. Some invert the caliber so the escapement faces forward. Some design the movement to be read from the front in the first place, as Cartier does in the skeleton calibers whose bridges are shaped into the brand's Roman numerals, so the structure of the movement is the dial.

Skeleton dial and skeletonised movement

The two are often confused and are not the same thing.

A skeleton dial exposes an otherwise ordinary movement. The bridges, plate and wheels beneath were made as they always are, and the interest comes from seeing them.

A skeletonised movement has itself been cut away: the mainplate, bridges and sometimes the barrel and rotor are pierced back to the metal that actually carries load, leaving a lattice. Traditionally this is done with a piercing saw and files, after which every newly created inside edge has to be bevelled and polished by hand, which is why properly skeletonised movements sit at the top of the price scale and why the finishing, rather than the holes, is the achievement.

Modern openworking is usually CNC milled or wire cut, which makes the holes cheap and changes nothing about the cost of the edges. That distinction is the whole economics of the category, and our guide to movement finishing explains why anglage, the beveling and polishing of those edges, is the part that takes hours per bridge and cannot be automated at the inward corners.

There is an engineering cost too. A mainplate exists to hold pivots in alignment, and metal removed from it is stiffness removed. Skeletonised calibers are therefore designed around what can be taken out rather than decorated after the fact, and they are not usually the movements you choose for hard wear.

Open heart and other half measures

Between a solid dial and a full skeleton there is a range of partial treatments, and the words are used loosely in listings. An open heart dial has one small aperture, usually at nine or twelve o'clock, showing only the balance in motion; Seiko has sold this on affordable automatics for years. A sapphire dial keeps a full dial surface with markers printed or applied on transparent glass. And some dials are simply printed with a movement-like pattern behind a conventional layout, which is a graphic effect and nothing more. If a listing says skeleton, look at whether you can actually see wheels turning or only a picture of them.

What good looks like

Judge it on contrast and on edges. The hands and markers need something to read against, so look for outlined or filled hands, a solid minute track, and a dial ring that separates the display from the busy background. On the movement, look at the inside angles of the cut-outs, whether the bevels are even and bright, and whether the decoration continues onto surfaces that were only created by the piercing.

The practical test is boring and effective: hold the watch at arm's length in ordinary indoor light and read the time without staring. If you find yourself hunting for the minute hand, no amount of finishing will fix that at seven in the morning. Anti-reflective coating on the crystal matters more here than on a solid dial, because there is no matte surface behind it to kill reflections.

Common misconceptions

A skeleton is the hardest kind of watch to read at a glance. There is no flat background, and lume is usually reduced or absent because there is little surface to carry it. If legibility matters to you, this is a design that asks you to give some up. Our guide to dials, hands and legibility covers what you are trading away.

It is also easy to assume that any open dial implies hand work. A stamped ring over a stock movement is an inexpensive effect, and it looks very different under a loupe from a plate that has been sawn out and finished, though the two can photograph much the same.

Two further assumptions are worth correcting. An open dial says nothing about the movement's complexity: a skeletonised three-hand automatic is still a three-hand automatic, and skeletonising is not a complication. And it does not weaken the case or the seals, so water resistance is unaffected. What it does affect is the bill at service time, since more finished surfaces are exposed to handling and dust shows against an open background. Indicative US figures put a full service on a three-hand automatic at $250 to $500 at an independent watchmaker before tax, and skeletonised work sits above that. Our service cost breakdown has the ranges.