Most expensive pocket watch sold at auction

The most expensive pocket watch sold at auction is the Henry Graves Jr Supercomplication, a gold, double-dialled watch crafted by hand between 1925 and 1932 by Patek Philippe of Switzerland. On 11 November 2014, the watch was sold for 23,237,000 Swiss Francs (£15,154,312; $24,073,532) at Sotheby’s in Geneva, Switzerland.

The watch measures 74 mm (2.91 in) in diameter (the same width as a typical smartphone) and is 37 mm (1.45 in) thick, including the domed glass covers on the front and rear faces. Despite its relatively compact size, it weighs 536 grams (1 lb 2.9 oz), which gives an idea of how densely packed the internal mechanisms are. It was sold in its original tulipwood box, inlaid with a mother-of-pearl panel featuring the arms of Henry Graves Jr (1868–1953) – the American banker who commissioned the piece in 1925.

The name of the piece is a reference to Graves’ desire to have the most “complicated” watch in the world. (In horogical terminology, a “complication” is any feature that a mechanical timepiece can perform in addition to telling the time. Common complications include calendars, phase-of-the-moon displays and stopwatch functions.)

The Supercomplication required three years of study in astronomy, mathematics and precision mechanics before a viable design could be finalized. The enormously elaborate mechanism uses 900 individual parts including 430 screws, 110 wheels, 120 various movable parts and 70 jeweled bearings. It took the artisans at Patek-Phillippe – assisted by several other prominent Swiss watchmakers acting as sub-contractors – more than five years to assemble the watch, finally delivering it to Graves on 19 Jan 1933.

The 24 “complications” of the watch include a star chart (calibrated to show the night sky over Graves’ Manhattan apartment on any given night) and a multi-year calendar that will be accurate until the year 2100, as well as various alarm and stopwatch functions. This number of complications remained unbeaten until 1989, when Patek-Philippe released the 33-complication “Calibre 89”. It remains, however, the most complicated watch to have been made without the assistance of computers.