IWC fans who are paying attention to the calendar should know by now that 2018 marks the 150-year anniversary of the well-known brand from Schaffhausen, Switzerland. Founded in 1868 by American watchmaker Florentine Ariosto Jones, IWC would slowly and gradually, over its one-and-a-half-century-long history, develop a reputation for solidly engineered watches – the company’s Latin motto, “Probus Scafusia,” translates to “good craftsmanship from Schaffhausen.” To celebrate the 150-year anniversary of the brand, IWC has just unveiled two high-tech tourbillon watches that clearly showcase the brand’s know-how in complicated watchmaking. Meet the new IWC Portugieser Perpetual Calendar Tourbillon Edition “150 Years” and the IWC Portugieser Constant-Force Tourbillon Edition “150 Years.”

The Portugieser Perpetual Calendar Tourbillon Edition “150 Years” is significant because it is the first time IWC has combined a perpetual calendar with a tourbillon on the dial. The watch comes in a 45mm wide Portugieser-style case, which IWC fans will instantly recognize from its distinctive short and curved lugs as well as the chunky knurled crown. Paired with a black Santoni alligator strap and water resistant to just 30m, it goes without saying that it should be kept away from water.

The dial is white and features a lacquered finish with large black Arabic numerals printed in the signature font of IWC’s Portugieser watches. Sizable heat-treated leaf-shaped hour and minute hands and a simple railroad-style minutes track ensure time can be easily read.

At 9 o’clock, you have the sub-dial that indicates the day, and at 3 o’clock you have the sub-dials that show the date and power reserve. At 6 o’clock, there’s a month indicator and moon phase display, and to the left of it at around 8 o’clock you have the year indicator. Finally, there’s the flying tourbillon that makes a single rotation every minute at 12 o’clock.

The movement within is the self-winding IWC caliber 51950, which is based on the Caliber 51900 found in IWC’s other tourbillon watches like the Portugieser Tourbillon Mystère Rétrograde but with the ingenious 82-part perpetual calendar module developed by Kurt Klaus. This movement also features IWC’s Pellaton winding system and has a generous power reserve of 168 hours, or 7 days. It is visible through a sapphire display caseback and comes with a special commemorative 18k gold rotor.

The other tourbillon watch that IWC has specially prepared for its 150th anniversary is the Portugieser Constant-Force Tourbillon Edition “150 Years.” This comes in a slightly larger 46mm wide Portugieser style case and is only available in platinum. Water resistance is a mere 30m, and the watch comes paired with a black alligator strap by Santoni.

The Portugieser Constant-Force Tourbillon Edition “150 Years” comes with a white lacquered dial with large black Arabic numerals printed in the signature font of IWC’s Portugieser watches. Like the earlier Portugieser Perpetual Calendar Tourbillon Edition “150 Years,” this watch also has heat-treated blue hour and minute hands. This is an updated version of previous Constant-Force Tourbillon watches – Portugieser and other models – combined with the “perpetual moon phase display.”

The Portugieser Constant-Force Tourbillon Edition “150 Years” has a considerably less busy dial. At 1 o’clock there is a moon phase display that only needs to be adjusted by a day after 577.5 years. Below the moon phase display at about 4:30 is a power reserve indicator. Finally, we have the highlight of the watch, the large tourbillon featuring a constant-force mechanism that delivers power in even impulses to the escapement. In theory, this should improve the chronometric performance of the movement.

The movement in this piece is the hand-wound IWC caliber 94805, which beats at a leisurely 2.5Hz and features 96 hours of power reserve. The movement can be admired through a sapphire display caseback and features an inlaid insignia that celebrates the 150th anniversary of the brand.

These two highly complex special anniversary watches will be produced in extremely small numbers. Only 50 pieces of the IWC Portugieser Perpetual Calendar Tourbillon Edition “150 Years” (Ref. IW504501) will be produced with a price of $110,000. On the other hand, the IWC Portugieser Constant-Force Tourbillon Edition “150 Years” (Ref. IW590202) is limited to just 15 pieces for a price of $253,000. iwc.com