In 2015 IWC will celebrate the 75th anniversary of the Portuguese. The first Portuguese was developed at the end of the 1930’s and featured the clean design, that we know the Portuguese for today. In the past 75 year it has grown?to become an entire collection, or family of watches as IWC calls it. There will be several ‘celebratory’ models and ‘updates’, and there’s the new IWC Portuguese Annual Calendar (Ref. 5035), which is IWC's very first annual calendar and it displays the month, date and day, in three separate, semicircular aperture?at 12 o'clock.?The new IWC Portuguese Annual Calendar shares, for a large part, the looks of the Portuguese Automatic, which is also powered by a 7-days automatic movement. In size it is slightly bigger, and with a diameter of 44,2mm and thickness of 15,3mm, it comes close to the dimensions of the Portuguese Perpetual Calendar. It’s?not the smallest watch, but that’s not what IWC is known for, at least not in the last decades. When the Portuguese was introduced, at the end of the 1930’s or beginning of the 1940’s, it was considered humongous?with its diameter of?43mm. Ad - Scroll to continue with article Calibre 52850 and the new?52000-calibre familyThe new Portuguese Annual Calendar will be powered by?the new IWC-manufactured calibre 52850. This movement is part of the renewed calibre 52000 calibres, which are updated versions of the 50000 family of calibres that were used up until now. They are all equipped with?two main spring barrels, delivering 168 hours of autonomy, when fully wound, and the IWC signature Pellaton winding system.The latter has been further improved: the pawls, automatic wheel and rotor bearing are now made of extremely hard, wear-resistant ceramic; and two barrels, rather than just one, build up an impressive 7-day power reserve with a frequency of 28,800 vph (4 hertz.)?The 52000-calibre family now features?slimmer proportions of the rotor, the improved Pellaton winding system,?an?engraved rotor made of solid 18-carat red gold and blued screws.The annual calendarThe two barrels provide a higher torque, which is required to drive the three calendar discs, displaying the month, date and day of the week. The annual calendar mechanism is newly developed and here’s a brief description of how it works:The hour wheel sets in motion the date advance wheel, which is equipped with two different advance fingers.One of the fingers is responsible for the date and month displays, the other for the weekday display.Every day, towards midnight, the date is moved forward with the help of the upper advance finger.The month display and the program wheel (which defines the lengths of the various months) are controlled by two pins on the date disc.The first of these pins advances the program wheel by one division. A feeler on the advance lever recognizes months with 30 days by a deeper notch on the program wheel and provides more space for it to switch. The following day, the advance lever ensures that the date moves forward by 2 days. The second pin in the date disc sets the new month.The IWC Portuguese Annual Calendar comes in three flavours: stainless steel with a silver-plated dial or with a midnight blue dial, or 18k red gold with a silver-plated dial. Each version comes with a black alligator leather strap and a folding clasp in the same material as the case.Don’t you just love the blue dial? Until now reserved for the Laureus model, like the Portuguese Chronograph Classic Edition Laureus that was introduced last year, but now for the first time a striking blue dial is introduced into the normal collection.?As soon as prices are known, we’ll update this article.