We laid our eyes on the Portugieser Eternal Calendar by IWC only a few months ago, and watch connoisseurs have already deemed this timepiece a technical marvel. The watch is programmed for a four-year cycle, but this timepiece is equipped with an eternal calendar designed to account for leap years through an ingenious additional module accurately.
This module, comprising just eight parts, completes a single revolution every four centuries and is programmed to skip three leap years in that period due to its ingenious design. It is a technical feat that has now been rightfully recognized by Guinness World Records as the "most accurate lunar phase wristwatch." Obtaining recognition from the Guinness World Records means that the accomplishment is notable and outstanding in a specific category or field. It serves as a prestigious acknowledgment of excellence and sets a benchmark that is widely recognized globally.
The moon phase complication display does not follow a simple daily rhythm due to the moon's irregular orbit of 29 days, 12 hours, 44 minutes, and 2.88 seconds. To ensure precise accuracy, IWC designed a new reduction gear train employing three intermediate wheels. This gear train ensures that the display deviates from the actual moon orbit by just one day every 45 million years, effectively mimicking the lunar cycle as closely as possible.
The Double Moon indication on the dial offers a portrayal of the lunar phase from both the Northern and Southern hemispheres. This presentation features two superimposed discs: a celestial disc with two small circular apertures rotating above a stationary lower disc adorned with a Guilloché pattern on titanium. The visual effect created resembles two moons waxing or waning in the sky.
The Portugieser Eternal Calendar has a platinum case with polished and brushed surfaces, complemented by a black alligator leather strap by Italian leather artisan Santoni, with a platinum folding clasp. The numerals and characteristic Portugieser minute scale are printed on a white lacquered flange, giving the texts and appliques an illusion that they are floating under the box-glass sapphire crystal, machined and polished painstakingly.
Additional features include the newly developed IWC-manufacture 52640 calibre, which integrates a highly efficient Pellaton winding system. This system uses rotor movements in both directions to establish a power reserve of seven days (168 hours) spread across two barrels.
