Piaget has long been associated with ultra-thin watchmaking. Back in 1957, the maison’s Calibre 9P was a hand-wound movement just 2mm thick and, in 1960, its 2.3mm-thick Calibre 12P was the world’s thinnest self-winding movement at the time. Today, Piaget continues to innovate in the ultra-thin segment, particularly with its Altiplano line. The Altiplano Ultimate Concept – which was first sighted in 2018 – is a boundary-pushing example that is continuing proof of Piaget’s watchmaking expertise.
This year, its globe trot showcases the Ultimate Concept – at 2mm thick in total – as the world’s thinnest mechanical watch. In its full realisation, it is an exercise in holistic watch design—this is not just about the thinnest movement, but the thinnest overall watch. This has necessarily required deep integration between movement and 41mm case—the latter made of a cobalt alloy which is as rigid as possible to prevent bending. Instead of the usual construction, where movement is sandwiched between caseback, dial and crystal, the Ultimate Concept consists of only two layers: the caseback, which doubles as the main plate and also houses the sapphire, and the movement components themselves.
These components are on full display, as a dial would only add bulk, and are arranged in as flat a plane as possible. The mainspring barrel is machined directly into the case back, and there is a curious lack of bridges—components are secured from the underside using ceramic ball bearings. Every opportunity to shed material was taken; for instance, the hour indicator is a recessed disc, which means only a single hand is needed for the minutes.
A unique challenge for a watch this thin is the winding mechanism. For starters, a crown less than 2mm in diameter would be too difficult to manipulate. The solution was a flat crown that is recessed into the case when not in use. There is also no room for the usual, vertically oriented crown wheel, and instead a special type of ‘infinite’ screw is used to translate the twisting of the crown into winding of the mainspring.
The crystal is a paper-thin sapphire slice just 0.2mm thick, and lies flush with the case when set. It is glued in precisely, and to enable servicing a small channel allows air to be introduced so that the pressure will aid in removing the crystal. Despite this, the Ultimate Concept has a water resistance of 3 bar—an impressive feat considering its demanding construction.
This technical feat is delivered in a package that is clean and somehow minimalist despite its complexity. The black PVD finishing and brushed surfaces are an understated, darkly modern look, but one that preserves the elegance that is also a Piaget hallmark.