The IWC Portugieser Perpetual Calendar 5021 was introduced in 2003, pairing IWC's self-winding 7-day movement with Kurt Klaus' ingenious perpetual calendar module. The latter was first seen in the 1985 Da Vinci and adapted to fit the larger dimensions of the 7-day movement. It featured a case of 44.2mm with sapphire glasses both front and back. One of its signature elements was the 'Double Moon' moonphase display, allowing its owner to read the moonphase in both the southern and northern hemisphere. The 5021 was accompanied by the slightly smaller 5022 ('Single Moon') in 2006.This reference, the 5021-05, features a pale yellow gold case with silver dial. It was introduced in 2003. Between 2003 and 2005 the 5021-05 had the 50611 calibre. This changed between 2005 and 2007 when it was powered by the 51612 calibre and finally by the 51614 calibre between 2007 and 2008.
