Less is more, so they say, and that seems to be the logic behind the Piaget Altiplano Ultimate 910P Automatic – the world's thinnest self-winding watch at only 4.30 mm thick. The result of three years of development, the latest example of ultra-thin haute horology is based on the manually-wound 2013 Piaget Altiplano 900P, which is the world's thinnest mechanical watch, coming in at 3.65 mm.

At a time when big watches are in vogue and everyone seems to be going around with dinner plates strapped to their wrists, it's refreshing to see a timepiece shrinking in at least one dimension. Piaget already has a reputation for over a century as a maker of ultra-thin components, including the 9P movement that was only 2 mm thick, but reducing the overall thickness of a watch is a tricky job that requires more than a little lateral thinking.

For example, we normally talk about a watch's movement and the case that contains it, but in the 910P, that distinction is meaningless. To reduce the thickness as much as possible, the makers have combined the 219-piece movement and case into a single unit. In other words, don't expect to see any images of the movement outside of the case because parts of it are the case, which acts as the mainplate of the calibre.

Another factor in shrinking the 910P was the development of extremely thin components, including wheels that are 0.12 mm thick. Some parts even had to made out of 22K gold to handle the level of fine machining required. This was combined with a new approach to the basic architecture of the movement.

Since the 910P has a diameter of 41 mm or about that of a largish dive watch, the designers could play around with it. The 30-jewel, 21,600 vph (3 Hz) movement's construction was reversed by putting the bridges on the same side as the dial and the display was placed off center to make room for the mechanism, which was no thicker than the balance wheel. In addition the 22K gold oscillating weight that powers the 50-hour reserve was put on the movement's periphery. Again, gold was chosen as much for its properties as aesthetics, allowing it to provide the needed inertia in as small a space as possible.

The position of the hands also had to be tweaked to accommodate the extreme thinness. Because there was a danger of the crystal pressing against them, they were moved under the bridges in case the glass became distorted under pressure.

The Piaget Altiplano Ultimate 910P comes with a Black alligator leather strap with matching gold buckle. It's available in white gold for US$27,000 and rose gold at $26,000.

Source: Piaget

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