Patek Philippe’s Henry Graves Supercomplication is back on the market, and will be the centrepiece of Sotheby’s Important Watches auction taking place in Geneva on 11 November. According to a Bloomberg report from 2012, the watch’s current owner is Sheikh Saud Bin Mohammed Bin Ali Al-Thani, a member of the Qatari royal family. Thani has pledged almost US$83 million worth of assets to Sotheby’s to cover debts owed to the auction house, including six watches, one of which is the Graves Supercomplication.

The Graves Supercomplication is arguably the most famous watch in the world. Henry Graves Jr, a New York banker, originally commissioned it in 1925 as part of a rivalry with automobile manufacturer James Ward Packard, to see who could own the world’s most complicated watch. In an era without computers and AutoCAD software, Patek Philippe’s watchmakers spent three years just designing the watch and a further five building it. The result was (take a deep breath now) a gold openface minute repeating pocket chronograph with Westminster chimes, moon phase indicator, perpetual calendar, sidereal time, power reserve and New York City’s sunrise and sunset times plus night time celestial chart. With 24 complications set inside an 18 karat gold case, the Graves Supercomplication weighs over a pound, and remained the most complicated watch in the world for 56 years after it was finished, before finally being surpassed by technicians with the aid of computer-assisted machines. Interestingly, the new record holder remained Patek Philippe, which had created the Calibre 89 with 33 complications using 1728 parts in 1989, to commemorate its 150^th anniversary.

The Graves Supercomplication last went under the hammer in 1999 for a record-breaking US$11 million, up from an initial estimate of US$3-5 million. Sotheby’s was also the auction house handling the sale then. Given that 2014 is Patek Philippe’s 175^th anniversary, there should be quite some interest in this timepiece…and correspondingly some very keen bidding between collectors. Sotheby’s current estimate for its value is CHF15 million.