The unique status of the Da Vinci Tourbillon Rétrograde Chronograph with the Reference IW393101 is reflected in the name alone. Uniting complications such as a chronograph, a tourbillon and a retrograde date display on an IWC dial for the first time called for a redesign of the IWC-manufactured 89900 calibre. A fully fledged tourbillon was integrated to replace the small seconds at “6 o’clock”. The company’s designers positioned the tourbillon cage on the original fourth wheel while the small seconds counter was transformed into a central seconds. The chronograph function remains at the top of the dial at “12 o’clock”. It enables the user to stop times up to 11 hours and 59 minutes and read them off as if on a normal watch face. On the retrograde date display, which describes a gentle arc across the left-hand side of the dial, the hand automatically jumps back to 1 after the 31st of the month. The new calibre features a “hacking” tourbillon that enables setting the time with down-to-the-second accuracy. In addition, the pallet and escape wheel are made of diamond-coated silicon, an extremely hard surface with good sliding properties that reduces friction and thus wear and tear. The reduction in friction also compensates for the increased energy used by the tourbillon, making it possible to retain the original 68-hour power reserve when fully wound. At 44 millimetres in diameter and with a height of 17 millimetres, the massive 18-carat red gold case of this timepiece makes a decidedly imposing impression. At the back of the watch, which is water-resistant to 3 bar, a glance through the transparent sapphire glass reveals the complex design of the new 89900 calibre movement.