The Patek Philippe novelty that probably attracted more attention at Baselworld 2017 is the new Reference 5320G Perpetual Calendar, i. e. a timepiece that automatically indicates months with 28, 30, and 31 days and every four years also recognizes the 29th of February as a leap day.
This new complication watch has the same face that has been Patek Philippe’s paragon for perpetual calendars since 1941: a double aperture for the day and month displays at 12 o’clock and a subsidiary dial at 6 o’clock for the analog date and the moon phases.
Additionally, the cream-colored dial now has a small day/night aperture between 7 and 8 o’clock and a second aperture for the leap year cycle symmetrically positioned between 4 and 5 o’clock.
Applied gold Arabic numerals and sharp-tipped luminous hands (a reminiscence of the Ref. 1463 chronograph from the 1950s), a slender sweep seconds hand, and the crisply graduate seconds scale assure excellent legibility. The moon phases will require a correction by one day only every 122 years.
Crafted from white gold, the 40 mm vintage-style case has a so-called box-type sapphire-crystal glass that clearly overlaps the bezel for a total height (crystal to display back) of 11.13 mm.
The three-tier lugs were inspired by the legendary Ref. 2405 that dates back to the 1950s.
The plate side is fitted with a modern sapphire-crystal case back that reveals the 4 Hz (28,800 vibrations per hour) Calibre 324 S Q movement: bridges with chamfered and polished edges, Geneva striping and gold-filled engravings, the Gyromax balance with the Spiromax balance spring made of Silinvar, and the solid-gold rotor suspended between ball bearings.
In terms of rate accuracy, the tolerance ranges from -3 to +2 seconds per day, in line with the directives of the Patek Philippe Seal. The power reserve is minimum 35, maximum 45 hours.