The IWC Portugieser Perpetual Calendar 5023 made its debut in 2010. It boasts a self-winding 7-day movement and an impressive perpetual calendar module by Kurt Klaus. Originally seen in the 1985 Da Vinci, it was perfectly adapted to fit the larger 7-day movement. The watch has a 44.2mm case and sapphire glass on both the front and back. One unique feature is the 'Single Moon' moonphase display, which accurately shows the moon's phase in its hemisphere. The IW5023-05 version, released in 2011, stands out with its platinum case and silver dial. Only 250 pieces were made, making it a coveted choice for any watch enthusiast