• Piaget’s enduring pursuit of ultra-thin watchmaking can be traced back to 1916, when the brand’s advertising already referenced ultra-thin components and movements. This ambition gained prominence in the 1940s, as Piaget explored the limits of thinness through pocket watches and a distinctive series of coin watches. Much like the present example, these coin watches were ingeniously crafted by slicing a twenty-dollar coin in half, embedding a miniature movement within, and securing it with a discreet clasp. When closed, the watch closely resembles the original coin, appearing only marginally thicker.

• The technical breakthrough that made this possible was the introduction of Piaget’s in-house ultra-thin calibre 9P in 1957, measuring just 2 mm in thickness. This movement became a cornerstone of Piaget’s identity and enabled the creation of elegant, minimalist timepieces that pushed the boundaries of traditional watchmaking.

• The present timepiece is a superb example of this innovation. It is housed within a twenty-dollar United States “Liberty” commemorative gold coin and powered by the legendary calibre 9P. The watch is in well-preserved condition, with the details on both the obverse and reverse of the coin remaining crisp and clearly defined. The case retains its original engravings, which are still crisp and deep. Enhancing its originality and charm, the watch is paired with its integrated 18K yellow gold bracelet, which complement the warm tones of the gold and reinforce the refined aesthetic of the piece. Accompanied by its full set of accessories, this timepiece represents a rare and historically significant example of Piaget’s mastery in ultra-thin horology and creative design.