In the 1980s, IWC struck upon what would become the definitive differentiating factor for mechanical watches Complications. Since quartz watches could not offer the variety of innovative complications long enjoyed in mechanical movements, a company could thrive against the competition from quartz by relying on their buyers' interest in unique and complicated watches. This was proven in 1985 with the release of Kurt Klaus' innovative Da Vinci Perpetual Calendar, giving the company the confidence to develop a truly unique and complicated watch.
The result of 7 years development work, the 1990 Grande Complication Ref. 3770 truly set IWC and the resurgent Swiss watch industry on a new path. One advertisement from the company claimed “The Grande Complication from IWC. Considered impossible, and therefore a historic great.” Another advertisement claimed “If something within the infinite range of mechanical watchmaking is considered unachievable, it has traditionally presented us with a challenge.”
The Grande Complication is powered by IWC's Cal. 79091, an automatic chronograph movement with perpetual calendar and moon phase indicator as well as a minute repeater (developed by Renaud et Papi). The 4-digit date display at 8 00 would become an IWC hallmark, as would the 4-subdial layout of chronograph and date pointers. The 42 mm case was large for 1990, but seems small by modern standards. It features a wide bezel covering the chime, which circles the dial.
The IWC Grande Complication was limited to just 50 pieces per year, yet it remained in production for over two decades. The watch was re-launched in late 2003 with the addition of a more contemporary dial and swallow hands, but the rest remained the same. Even after the 2010 launch of the successor “Portugieser” model, the original Grande Complication remained in production in limited numbers.
At SIHH in 2010, IWC launched a new Grande Complication. As the name suggests, the Portugieser Grande Complication features the Portugieser case and style, yet retains the same Cal. 79091 movement as the original 1990 Grande Complication. The case is dramatically larger at 45 mm, with the subdials clustered closer to the center than before thanks to a narrow bezel. This is made possible by precisely positioning the chime relative to the thin bezel and crystal. The new Portugieser is also waterproof to 3 bar thanks to better sealing around the repeater switch.
IWC limited production of the Portugieser Grande Complication to 250 examples each in platinum and red gold. They remain in the company catalog as of 2018.