This is the first time that IWC has built its perpetual calendar complication – developed in the 1980s by Kurt Klaus – into an 82000 series in-house calibre. The resulting 82650 movement is fitted inside the smaller 42mm case of this Portugieser Perpetual Calendar. A Pellaton automatic winding system provides 60 hours of power reserve. Each of the calendar indications is adjusted by the crown. Day, date and month are distributed over three subdials, with an aperture in the day display for the leap year indication. The perpetual moon phase display, which diverges by just one day after 577.5 years, sits inside the month display. A boutique edition is proposed in 18k red gold with blue dial, gold-plated hands and a blue alligator strap by Santoni.