Portuguese Perpetual Calendar 5021 Red Gold / Ardoise

In Context

At 44.2 mm it is a large watch — well above this catalogue’s 40 mm median, and enough to dominate a narrow wrist. At 15.5 mm it is a tall case, and it will catch on a cuff. The case back is open, so the movement is visible without taking the watch apart, and the sapphire crystal will resist everything short of deliberate abuse. Rated to 30 m, it is protected against rain and splashes and nothing beyond that.

The movement winds itself from the motion of your wrist. 168 hours of reserve puts it well past a weekend — several days off the wrist and it is still going. At 21,600 vph the seconds hand advances 6 times a second, the slower and more audible rate of an older design.

IW502123 stands on its own in this catalogue — no other reference here shares its base number. It pairs a black dial with a red gold case. It was a limited edition. Beyond the time it carries a perpetual calendar.

The 51614 is IWC's seven-day perpetual calendar, the Pellaton automatic with a single oversized barrel and Kurt Klaus's calendar module. It shows the date, day, month, four-digit year and moon phase, all set from the crown. It powers 19 watches in this library. The 51000 family stores 168 hours in one barrel and beats slowly at 21,600 vph to make that possible, with 62 jewels at 38.2 mm across; the calendar is programmed to 2499 and needs no correctors. The 51614 is the 2007 revision of the 50611 of 2003 and the 51612 of 2005, which powered the Portugieser Perpetual Calendar from its launch. The glossary defines the [perpetual calendar](/glossary/perpetual-calendar), and the Journal's [Pellaton piece](/blog/iwc-pellaton-winding) explains the winding system and the 168-hour figure. In the library it powers 10 [Big Pilot](/brands/iwc/big-pilot) Perpetual Calendar references at 46.2 mm and 9 [Portugieser](/brands/iwc/portugieser) Perpetual Calendar 5021 references at 44.2 mm. 11 are limited editions. The [52615](/calibers/iwc-52615) is the two-barrel successor of 2015, and the [51111](/calibers/iwc-51111) the same base without the calendar.

18 other watches in the library run the IWC 51614.

IWC

Big Pilot Perpetual Calendar Stainless Steel / Black / Association Monegasque Contre Myopathie

IW5026-02 · 46.2 mm

IWC

Big Pilot Perpetual Calendar Platinum / Black / Sincere

IW5026-05 · 46.2 mm

IWC

Big Pilot Perpetual Calendar Titanium / Black / Cellini

IW5026-06 · 46.2 mm

IWC

Big Pilot Perpetual Calendar Stainless Steel / Black / Bucherer

IW5026-07 · 46.2 mm