The Portuguese Tourbillon Mystère Rétrograde is a mysteriously attractive timepiece with a flying tourbillon and retrograde date display that automatically reverts to its starting position at the end of the month. The seven-day power reserve display tells the wearer how much energy remains in the IWC-manufactured 51900 calibre. To mark the 75th anniversary of the Portugieser (Portuguese) watch family, IWC has given a timepiece swathed in mystery an additional touch of luxury. The arched-edge front glass endows the watch with a more classic, balanced appearance. The horns have also been ergonomically optimized to make the watch more comfortable to wear on a slimmer wrist. Another new feature is the exclusive alligator leather strap by Santoni. The reverse side of the watch with its see-through sapphire-glass back is also more attractive. The narrower and partly perforated rotor – now made of solid red gold – provides a generous view of the IWC-manufactured calibre, which also features blued screws.