Uploaded January 2026 | Updated September 2026, 1 week ago
Inside the Eternal Calendar: Assembling the IW505701
Awarded the “Aiguille d’Or” at the 24th Grand Prix d’Horlogerie de Genève, the Portugieser Eternal Calendar IW505701 is IWC’s first secular perpetual calendar - a watch that measures time on an extraordinary scale.
Its platinum 44.2 mm case houses the hand-wound 52640 calibre, featuring a 7-day power reserve across two barrels, a 400-year gear that automatically skips three leap years (years divisible by 100 but not by 400), and a Double Moon™ display accurate to one day in over 45 million years.
The IW505701 makes extensive use of glass elements, including box-glass sapphire crystals on the front and back, which offer an unobstructed view of the movement. The transparent dial and finely finished components reveal IWC’s mastery of mechanical calendars, including the 4-digit year display, along with day, date, month, and moonphase indicators.
Water-resistant to 5 bar, fitted with a platinum folding clasp and Santoni alligator strap, the IW505701 is a testament to IWC’s horological ingenuity, timeless craftsmanship, and mechanical precision.
#IWCwatches | #IWCportugieser
Inside the Eternal Calendar: Assembling the IW505701
Awarded the “Aiguille d’Or” at the 24th Grand Prix d’Horlogerie de Genève, the Portugieser Eternal Calendar IW505701 is IWC’s first secular perpetual calendar - a watch that measures time on an extraordinary scale.
Its platinum 44.2 mm case houses the hand-wound 52640 calibre, featuring a 7-day power reserve across two barrels, a 400-year gear that automatically skips three leap years (years divisible by 100 but not by 400), and a Double Moon™ display accurate to one day in over 45 million years.
The IW505701 makes extensive use of glass elements, including box-glass sapphire crystals on the front and back, which offer an unobstructed view of the movement. The transparent dial and finely finished components reveal IWC’s mastery of mechanical calendars, including the 4-digit year display, along with day, date, month, and moonphase indicators.
Water-resistant to 5 bar, fitted with a platinum folding clasp and Santoni alligator strap, the IW505701 is a testament to IWC’s horological ingenuity, timeless craftsmanship, and mechanical precision.
#IWCwatches | #IWCportugieser
