The 5711/1A is the steel Nautilus with date that Patek Philippe introduced in 2006, thirty years after Gérald Genta's original Nautilus.
The design remained recognisable: the porthole-shaped case with its two 'ears' at the sides, the octagonal bezel, the horizontally embossed dial and the bracelet integrated into the case.
The best-known version has a blue dial that darkens towards black at the edge; a white dial was among the other versions.
Inside is a self-winding movement with a gold central rotor, visible through the sapphire caseback: first calibre 324 S C, and in later examples the 26-330 S C. The watch is water-resistant to 120 metres.
In 2021 Patek Philippe withdrew the 5711/1A from the collection; in 2022 the white gold 5811/1G followed.
On a pre-owned 5711/1A we pay particular attention to the finishing. The alternation of brushed and polished surfaces on case and bracelet is characteristic, and inexpert polishing rounds off the edges.
We also compare the numbers on case and movement with the certificate, examine the dial and check the clasp. What a complete set includes is explained in our guide to box and papers.