Launched in 2015, the IW5035 family introduces the Annual Calendar complication to the Portugieser (aka Portuguese) collection. The month, date and day are displayed through three arched windows at 12 o'clock. The present version, reference IW503502, has a stainless steel case and a blue dial.
Located at “12 o’clock” on the dial, IWC’s annual calendar shows the month, date and day in three separate windows. The mechanism automatically takes into account the differing lengths of individual months. Unlike a perpetual calendar, however, the annual calendar is unable to make allowance for the leap days in February or the leap years. Once a year, then, at the end of February, it requires manual correction. In the case of IWC’s annual calendar, the correction is made simply, via the crown.