The Portuguese Grande Complication (Ref. 3776) has a total of 20 different displays and functions. The Calibre 79091 powers the chronograph functions, a perpetual calendar with displays for the date, day, month, year, decade and century as well as a perpetual moon phase and, supreme achievement in the art of mechanical watchmaking, the minute repeater.
The watch is available in 18-carat red gold or platinum.
To mark the 75th anniversary of the Portuguese watch family, the Grande Complication model appears with a number of understated modifications. The silver-plated dial, for instance, no longer features an engraving of the globe showing the lines of latitude and longitude. Because of this, it appears more composed, and the typical characteristics of the Portuguese – feuille hands, appliquéd Arabic numerals and railway-track-style chapter ring – are set off to better advantage. In the new collection, the case back is decorated with an engraved compass rose. The newly designed ergonomic strap horns are closer to the wrist and make the watch more comfortable to wear.
Between 1983 and 1985, master watchmaker Kurt Klaus designed and built the perpetual calendar for IWC Schaffhausen. It is mechanically programmed until 2499 and will require correction on just three occasions (in 2100, 2200 and 2300). What is more, the perpetual calendar has its own program to fulfil, and unlike the time display, does not need to be driven continuously.
Instead of this, it is given a mechanical impulse that advances it between 8 p.m. and 1 a.m. The perpetual calendar is operated simply, via the crown.
The moon phase display, too, will be just 1 day out of sync after 122 years.
The complex minute repeating strike train chimes with lower chimes for the hours, a double strike for the quarter-hours and a strike on the higherpitched gong for the minutes. Each gong is individually made by hand and then carefully tuned for pitch and tonal purity.
The watch is supplied with a Santoni alligator leather strap; the strap on the 18-carat red gold version is stitched with red gold thread while the strap on the exclusive platinum model is finished with a platinum thread. Both versions are limited to 250 watches.