As the name suggests, a “skeletonised” watch is one in which the movement has been reduced to its bare bones; where all but the thinnest strips of metal needed to connect the moving parts have been cut away and discarded. This idea dates back as far as the 18th century, when a watchmaker named Mr André-Charles Caron realised that by revealing the mechanics of the watch, he could offer his most prestigious clients something especially captivating. However, because skeletonising a movement properly by hand is incredibly difficult, time-consuming and risks fatally weakening a watch’s construction, it remained a very niche practice until the tail end of the 20th century. Yet once the watch industry reinvented itself as a luxury business, skeletonisation became much more desirable. During that era, a range of brands worked with the idea, from Jaeger-LeCoultre to Omega.

In the late 1990s, the game changed once again with the introduction of precision machinery, which could replace the role of the artisan and cut out the intricate shapes necessary to make a skeletonised movement. That brought skeletonisation to a much wider market, and enabled the creation of increasingly geometric, wiry designs like those popularised by Richard Mille and Roger Dubuis. The skeletonised aesthetic has now trickled down into the mainstream, leading to a new wave of watches with cutaway or “openworked” dials that expose and emphasise the mechanics of the movement below. Here are five of the finest currently available on MR PORTER.

Roger Dubuis has developed a unique visual language that relies heavily on skeletonisation. All but a couple of its men’s watches are skeletonised, to the extent that it has become the brand’s most recognisable trait. Central to that (literally and figuratively) is the five-pointed star motif that recurs across models; the jagged lines provide a powerful visual contrast to the wheels of the gear train, balance wheel and automatic rotor (at 11 o’clock). This ability to produce some of the thinnest, most extreme skeleton movements in the world is thanks to the extensive use of carbon fibre and titanium, which in turn add to the difficulty of production. The focus on materials extends beyond the case; as part of a partnership with tyremaker Pirelli, the strap is made from rubber previously used in race-winning Formula 1 tyres.

Cartier’s approach to skeletonisation is unlike that of any other brand. Whether it’s on its straightforward shapes, such as the Rotonde de Cartier, or on more challenging templates such as the Crash, the brand always manages to combine the skeletonised framework of the movement with its trademark Roman numerals. Thus the spines of the skeleton make up the hour markers as they would appear on the dial. This Santos is no different, although in a nod to current trends for ever-more minimalist dials, only 3,6,9 and 12 are represented numerically, alongside additional struts that keep the whole thing in place. The “dial” is coated with a layer of amorphous diamond-like carbon (ADLC), which, along with the titanium case, gives it a modern feel while also providing a scratch-proof surface. As you can see from the absence of a winding rotor, the in-house 9612 MC movement is hand-wound, and when fully charged offers a power reserve of 72 hours.

Girard-Perregaux’s Laureato is one of the original sports-luxe models that, in the 1970s, redefined the concept of a luxury watch by proving that stainless steel could play a key role – if the design was right. This skeletonised variation makes the most of the tension between the modern, geometric shapes of the case, bezel and bracelet and the curved, classical stylings of the skeletonised movement. Whereas a decade ago the movement would have been classically decorated with fine polishes and hand-engraving, today it is given a more subtle anthracite grey coating that further subverts the traditional idea of skeletonisation. Water-resistant to 100m, the Laureato Skeleton uses an in-house automatic movement with 54 hours’ power reserve.

For 50 years, Zenith has been making some of the world’s most impressive chronograph movements. It was among the first to produce an automatic chronograph in 1969, hence the Esperanto-derived name El Primero. But it's only relatively recently that Zenith has begun to make watches that fully showcase its expertise from the dial side. The Defy El Primero 21 is a particularly showstopping chronograph, able to measure time down to a 100th of a second thanks to a super-fast secondary escapement, visible between 10 and 11 o’clock. When running, the central chronograph’s second hand makes one rotation of the dial every second. The movement isn’t as heavily skeletonised as some, instead preferring to draw on its dense complexity and a sense of depth accentuated by the colour treatments applied to the bridges and plates.

TAG Heuer, with the launch of the Carrera Heuer-01 in 2015, reinvented an icon, the first overhaul to its venerable chronograph reference in a generation. It brought the watch into the 21st century, adding a thicker bezel, a more muscular case and futuristic typography. Most notably of all, however, it did away with the dial, opting for the first time to employ a skeletonised, openworked approach to showcase the in-house chronograph movement. The skeletonisation extends to the chronograph subdials and even the date function, which uses a disc of stencilled black numbers over a fixed white background, rather than the normal printed disc of dates. This version adds a GMT function, which uses an arrowhead hand and day-night 24-hour bezel to indicate time in a second time zone. The movement was upgraded at the same time – it’s now the Calibre Heuer 02, an automatic with 75 hours of power in the tank.