he Swiss watch industry faced challenging times when in 1985 IWC presented a perpetual calendar. Developed by Kurt Klaus, as Europa Star then reported (see below), its mechanism recognises the varying length of the months and every four years inserts a leap day at the end of February.

Klaus’s calendar set a benchmark for efficiency and simplicity of use. From these beginnings, the Schaffhausen brand has built a reputation for its expertise in mechanical calendars. Almost 40 years on, this expertise has earned the watch world’s ultimate accolade: the Grand Prix d’Horlogerie de Genève Aiguille d’Or.

©Archives Europa Star

©Archives Europa Star

©Archives Europa Star

A selection of Europa Star archives on the iconic perpetual calendar developed by IWC in the mid-1980s.

©Archives Europa Star

The prize was presented for the Portugieser Eternal Calendar. IWC’s first secular perpetual calendar, it is based on the synchronised design of the regular perpetual calendar, meaning all the displays are advanced by a single crown. Whereas a perpetual calendar requires adjustment in a centurial year that is not a leap year, the secular perpetual calendar is mechanically programmed to take such irregularities into consideration.

Thanks to a newly engineered 400-year gear, which completes one revolution in four centuries, the calendar skips three leap years over 400 years – the next time a leap year will be skipped is in 2100. As a result, this eternal calendar will accurately calculate leap years until 3999 (it has yet to be officially decided whether 4000 will be a leap year or not).

Another standout feature of this Portugieser Eternal Calendar is the moon-phase display. After simulating more than 22 trillion possible combinations, IWC’s engineers devised a reduction gear train composed of three intermediate wheels. The Double Moon™ indication, distinguished by a titanium disc with two blue dots and a glass disc rotating above it, will require adjustment only after 45 million years.

Calibre 52640, whose two barrels provide seven days (168 hours) of power reserve, is the first IWC movement to incorporate elements in glass, such as the barrel bridge. A timepiece not just for years but for centuries to come.

2024 PRIZE LIST

• “Aiguille d’Or” Grand Prix: IWC Schaffhausen, Portugieser Eternal Calendar
• Audacity Prize: Berneron, Mirage Sienna
• Eco-innovation Prize: Chopard, L.U.C Qualité Fleurier
• Chronometry Prize: Bernhard Lederer, 3 Times Certified Observatory Chronometer
• “Horological Revelation” Prize: Rémy Cools, Tourbillon Atelier
• Iconic Watch Prize: Piaget, Piaget Polo 79
• Tourbillon Watch Prize: Daniel Roth, Tourbillon Souscription
• Calendar and Astronomy Watch Prize: Laurent Ferrier, Classic Moon Silver
• Mechanical Exception Watch Prize: Bovet 1822, Récital 28 Prowess 1
• Chronograph Watch Prize: Massena Lab, Chronograph Monopoussoir Sylvain Pinaud x Massena Lab
• Sports Watch Prize: Ming, 37.09 Bluefin
• Men’s Complication Watch Prize: De Bethune, DB Kind Of Grande Complication
• Men’s Watch Prize: Voutilainen, KV20i Reversed
• Time Only Watch Prize: H. Moser & Cie, Streamliner Small Seconds Blue Enamel
• Jewellery Watch Prize: Chopard, Laguna High-Jewellery Secret Watch
• Artistic Crafts Watch Prize: Van Cleef & Arpels, Lady Arpels Jour Enchanté
• Ladies’ Complication Watch Prize: Van Cleef & Arpels, Lady Arpels Brise d’Été
• Ladies’ Watch Prize: Van Cleef & Arpels, Lady Jour Nuit
• “Petite Aiguille” Watch Prize: Kudoke, 3 Salmon
• Challenge Watch Prize: Otsuka Lotec, No.6
• Special Jury Prize: Jean-Pierre Hagmann