The Piaget Altiplano story begins in 1957, when the manufacture in La Côte-aux-Fées introduced the calibre 9P, a manually wound movement only 2 mm thick. The 9P measures 20.5 mm in diameter, beats at 19,800 vibrations per hour, has 89 components and offers about 36 hours of power reserve; it shows hours and minutes only and is decorated with vertical Côtes de Genève. According to Monochrome, every part of it was conceived and assembled by hand, at a time when computer-aided design barely existed. The 9P was cased in slim gold dress watches whose wide dials it made possible, and those early 9P models are the watches the brand later grouped under the Altiplano name. Its importance is that it launched the brand’s family of ultra-thin calibres, which now numbers more than 25 movements.

Because the movement was so flat, designers could use a broad dial opening and extremely thin cases, which suited both men’s dress watches and the bold bracelet and jewellery watches Piaget produced in the 1960s and 1970s. A 1961 example offered by Phillips, for instance, pairs the 9P with an 18k three-colour gold case and integrated textured bracelet and a champagne dial. In 1960 the brand followed with the automatic calibre 12P, about 2.3 mm thick thanks to a micro-rotor. The line has continued through the 9P2, the manual 430P and the automatic 1200P, and in 2017 the brand marked 60 years of the 9P with limited Altiplano 60th Anniversary watches in 18k white gold, 38 mm with the 430P and 43 mm with the 1200P. In 2018 the Altiplano Ultimate Concept reduced a complete mechanical watch to 2 mm.

Collectors and the watch press treat the 9P as a reference point in ultra-thin watchmaking, and forum discussions on WatchProSite describe the movement as a work of art, while regretting that it is usually hidden behind a solid case back. Vintage 9P watches are less common on the market than comparable dress watches from Jaeger-LeCoultre or Rolex, and enthusiasts report that their prices have been rising, especially for unusual shapes, coloured dials and integrated bracelets. The original 1957 calibre 9P watches are no longer produced, but the Altiplano is in production today as Piaget‘s main ultra-thin collection, now powered by successors such as the 430P and 1200P.