IWC Schaffhausen’s perpetual calendar was originally developed in the 1980s by former head watchmaker Kurt Klaus. The legendary complication made its debut in the Portugieser collection in 2003 and has since become one of its defining features.

The Portugieser Perpetual Calendar IW503702 features a polished 18-carat Armor Gold® case measuring 44.4mm in diameter, paired with an Obsidian dial, gold-plated hands and gold appliqués. A refined case construction, featuring a thinner casing ring and double-box sapphire crystals, gives the watch an especially elegant profile.

The intricately crafted dial is produced through a complex 60-step process. Fifteen layers of transparent lacquer are applied before the surface is fine-ground and polished to a high-gloss finish, creating an exceptional sense of depth.

Its perpetual calendar automatically recognises the different lengths of the months and accounts for the leap day every four years. All displays are synchronised and can be conveniently adjusted using the crown.

IWC’s characteristic Double Moon™ display depicts the moon as viewed from both the Northern and Southern Hemispheres. Thanks to a specially designed reduction gear, the display will deviate from the moon’s actual orbit by just one day after 577.7 years.

Powering the watch is the IWC-manufactured 52616 calibre, assembled from 386 individual components. Its automatic Pellaton winding system incorporates virtually wear-free zirconium oxide ceramic components, while the oscillating mass is crafted from solid gold. The system efficiently converts movement of the wearer’s wrist into energy, providing a seven-day power reserve across two barrels.

The watch is completed by a black Santoni alligator leather strap with an 18-carat Armor Gold® folding clasp.