IWC Portuguese Perpetual Calendar Watch shows the right day, date, month and year in four digits and requires no adjustment for short months or leap years. It also has a moonphase display which illustrates the waxing and the waning of the moon and deviates from the moon’s actual progress by just 12 seconds in each lunar period (29 days, 12 hours, 44 minutes and 3 seconds). Thus, it will add up to a deviation of just one day after 577.5 years.
The watch is housed in a round case measuring 44.2 mm in diameter and 15.5 mm in thickness. On the right side of the case, there is a screw-in crown. Depending on a model, there is a choice for the cases’ materials among platinum, 18-karat white gold and 18-karat red gold. The case includes a narrow fixed bezel crafted from the same metal as its case. Portuguese Perpetual Calendar is shielded on both sides by convex sapphire glasses with antireflective coatings which protects the case from scratches and provides water resistance to 30 meters (100 feet).
This Portuguese, like almost all models from Portuguese Family, has a transparent sapphire-glass case back that shows the inner beauty of the IWC-manufactured Caliber 51613. The in-house made mechanical movement, with Pellaton automatic winding system, a breguet spring and a Rotor with 18-karat yellow gold medallion, preserves impressive 168 hours of power reserve when fully wound. The powerful movement is built on 62 jewels and produces 21,600 vibrations per hour.
Various Functions Synchronized with One Another
A silver-plated, a silver colored or an ardoise dial serve as an ideal background for the leaf-styled hands, Arabic numerals and indices crafted from the same materials as their cases (platinum, 18-karat white gold or 18-karat red gold).
The modern and elegant dial comprises four sub-dials. The first one, at the 12 o’clock position, is a moonphase indicator. The Swiss manufacturer perfectly describes it as a grand-scale theatre on a tiny stage. On two models, it features a red-gold-plated moon against a blue background. This warm tone provides a pleasing contrast to the silver dial.
A seven day power reserve indicator and a date display are combined in a single totalizer situated at the 3 o’clock position. The next in line is a month sub-dial located at the 6 o’clock position. The fourth counter at the 9 o’clock position shows the day of the week and it is used in conjunction with the small hacking seconds.
Finally, the year in four digits is available in a small aperture situated between 7 and 8 o’clock positions. There is also a railway track-style chapter ring which nicely rounds the dial.
The Masterfully Engineered Wristwatch Available in Three Variants
IWC offers three versions of this Portuguese timepiece. A platinum model with the referent number IW502305 is limited to 250 pieces and comes with the price tag of approximately $60,000. This model is attached to a black alligator leather strap with a folding clasp in platinum. Two other models are more affordable. The white gold Portuguese Perpetual Calendar wristwatch with the reference IW502307 can be purchased for $41,000, while the red gold variant with the referent number IW502306 comes with the retail price of $37,000. The first one is attached to a dark brown alligator leather strap, while for the red gold model IWC has chosen a brighter brown color.
I have almost forgotten to mention that the mechanical perpetual calendar of this model takes into account every leap day in the Gregorian calendar and requires only one adjustment in 2100 at the end of February, but I guess you will not need it unless you plan to live for another 90 years
If you fancy Perpetual Calendar timepieces from IWC, I recommend the reviews of Portuguese Perpetual Calendar Double Moonphase Watch with the reference IW5032, Big Pilots Watch Perpetual Calendar Edition Antoine de Saint-Exupéry and Da Vinci Perpetual Calendar Edition Kurt Klaus.