To maintain the dial’s symmetry and simplicity, IWC placed the power-reserve display on the back of the movement, IWC’s in-house, manual-winding Caliber 59215, which can be viewed through a sapphire exhibition caseback. The movement is generously proportioned, at 37.8 millimeters in diameter, and supplies the watch with power for a full eight days. In fact, were it not for an intelligent system designed by IWC — which blocks the movement after the first 192 hours, stopping it before all the tension in the spring has been exhausted and thus eliminating the danger of reduced torque in the mainspring and the resulting loss of accuracy — the watch could run for nearly nine days without needing winding. The Glucydur-beryllium alloy indexless balance oscillates at a frequency of 4 hertz, or 28,800 vph. The Breguet spring, bent into shape using traditional watchmaking techniques, also aids in timekeeping precision. The coved bezel, another typical design element of the Portugieser line, and the arched-edge sapphire crystal, help to make the case appear less bulky despite its 12-millimeter thickness and 43-millimeter diameter.
The rose gold version of the IWC Portugieser Hand-Wound Eight Days Edition “75th Anniversary” will be available in a limited edition of 175 pieces, priced at $22,000; the stainless-steel version is limited to 750 watches and priced at $11,000. Both models are fitted with alligator leather straps produced by Italian shoe manufacturer Santoni.