The independent watchmaker Konstantin Chaykin had mulled over all the options. He could make all of his proposed watch’s components thinner, but then some would not work as well as needed. He could make the case very strong to compensate – that was an idea worth pursuing. Gold wouldn’t be durable enough. A tungsten nickel alloy would work, although it alone would take two months of machining – and he would need to use the rare, non-magnetic variety typically used in the development of space technology.
He could also rearrange the movement’s architecture, effectively splitting the mainspring barrel – a mechanical watch’s power source – into two parts, and integrate parts of the movement directly into the caseback. The winding of what would remain a very delicate instrument would need to be outsourced to a separate, dedicated device. But it could be done.
‘It’s like a magic trick: you know it’s there on your wrist, but you can’t feel it’
Konstantin Chaykin
Making of the ThinKing Mystery
And, in fact, it has been. Chaykin recently unveiled the result: the production version of his ThinKing mechanical watch, the world’s thinnest, at just 1.65mm deep. 'Making a watch that thin was a real challenge, but life would be very ordinary without it,' says Chaykin. 'Why do it? Because it’s like a magic trick: you know it’s there on your wrist, but you can’t feel it. Now we’re just waiting for the next guys to try to beat our record.'
Chaykin’s watch beat the record previously held by Bulgari, which in 2025 also released the world’s thinnest tourbillon movement, the Octo Finissimo Ultra Tourbillon (among our pick of the year's statement watches), at 1.85mm thick – again achieved by using the caseback as the movement’s manipulation. This, in turn, unseated Piaget’s Altiplano Ultimate Concept Tourbillon, at a positively chunky 2mm.
But why this arms race for an ever-more barely-there mechanical model? After all, it’s one which, arguably, has been in play since the master watchmaker Jean-Antoine Lepine reimagined the pocket watch way back in 1765, doing away with the movement’s traditional sandwich of plates and pillars for a greatly thinned-down timepiece, with Jacques-David LeCoultre, in 1907, and Audemars Piguet, in 1938, both further revolutionising movement architecture to produce, respectively, a 1.38mm-thick pocket-watch movement and a 1.64mm-thick wristwatch movement (not including the case). Since the 1950s, Vacheron Constantin, Jaeger-LeCoultre, Piaget, Audemars Piguet and, latterly, Bulgari and Richard Mille have led the competition for ever more thinness.
'For watchmakers, thinness is something of an obsession, because to achieve it you have to reimagine the components and produce them in different ways, using different materials. And for the collector who understands the technical aspects, a very thin watch is a point of difference,' explains Bulgari’s product creation executive director Fabrizio Buonamassa Stigliani. 'For me, honestly, thinness alone adds nothing to the functionality of a watch – if it’s not automatic and robust enough for everyday life then it’s more a prototype. And we’re at a place where we could make an even thinner prototype watch, but you wouldn’t be able to touch it.'
Indeed, Stigliani adds that pursuing thinness in a watch is always a matter of compromise: you take something away here, you lose something – like a useful level of power reserve, reliability or enough rigidity – there. Further problems of functionality include, he suggests, how to attach a strap or bracelet to a very thin watch, and, invariably, its aesthetic. 'Sometimes an ultra-thin watch just looks too flat, too fragile,' he says.
‘For the collector who understands the technical aspects, a very thin watch is a point of difference’
Fabrizio Buonamassa Stigliani, Bulgari’s product creation executive director
These various complications are why, Stigliani suggests, makers of ultra-thin watches belong to 'a club with only a few brands for members' who like to be able to 'show the market something completely new and [for whom an ultra-thin watch] is a bit of a technical show-off too. It’s a wow moment. And the record [achieved] is another form of advertising campaign.'
Perhaps, then, we’re close to peak thin – at least until some new wonder material comes along. Chaykin says he’s working on various ideas that would allow for an even thinner mechanical watch, but concedes that 'like breaking a record in sport, each new record gets harder to beat, and tends to take much longer'. And he agrees with Stigliani that breaking records is one thing, 'but making a watch that’s wearable is something else'.
But that’s not to say that more thinness – if not of the ultra kind – doesn’t have its uses. Thomas Van Straaten, founder of VPC Watch Co, for example, has recently launched its Type 39VM, recognised as the thinnest 200m automatic dive watch on the market, at 9.34mm total thickness. He argues that, beyond the cliché of a thin watch sitting nicely under a shirt cuff ('though actually that’s quite nice’, he says), thinness does make for a more comfortable watch to wear.
'The interest in thinness now isn’t a fad,' he adds, 'but fits with a growing appreciation for the ergonomics of watch design, which is also behind the greater number of smaller watches too. And thinness has to be in balance with the rest of the design. I’m not a fan of thinness for its own sake. We could have made the Type 39 thinner [albeit at some cost to water resistance] by using a printed dial instead of one with raised indices, but it just didn’t look as good. And that matters.'