Celebrating the Portugieser watch collection's 75th anniversary, IWC has launched the new IWC Portugieser Annual Calendar - first developed in the 1930s by IWC in response to two Portuguese gentlemen searching for a wristwatch with the same precision of a marine chronometer. Some of IWC's greatest complications have been contained within the Portugieser family, from the minute repeater to a constant-force tourbillon, and now with a new in-house calibre, the Annual Calendar. The 44.2mm stainless steel case houses a silver-plated dial that features a classic railway minute track ring with Arabic numerals within. Replacing the 11, 12 and 1 o'clock numerals is the tri-aperture annual calendar function. Displaying the month, date and day of the week, the calendar only requires adjusting, via the crown, once a year in February. At 9 o'clock is the small seconds sub-dial, while at 3 o'clock is the 7-day power reserve indicator. Visible through the sapphire crystal case back is the new IWC Swiss-made calibre 52850 that powers the Annual Calendar. Presented on a black Santoni alligator leather strap, this IWC Portugieser is secure with a stainless steel folding clasp.