In 1972, Gerald Genta sketched the Royal Oak in a single evening, under pressure to deliver something Audemars Piguet had never attempted: a luxury sports watch in steel, priced and finished as though it were gold. The idea seemed contradictory at the time. Five decades on, it is the reference against which every subsequent steel sports watch has been measured.

Reference 56175ST belongs to the smaller Royal Oak family, with a more compact case size that predates the larger references which would later dominate the line, and which many collectors now consider the more elegant proportion. The octagonal bezel, secured by its eight visible hexagonal screws, sits atop a case whose finishing alternates between brushed and polished surfaces with the precision that defines every Royal Oak regardless of era.

The dial carries the Tapisserie guilloché pattern: a waffle-textured surface, hand-guilloché in the AP workshops, that catches and scatters light in a way no printed dial can replicate. Applied baton indices and the AP signature sit cleanly against it, with a date window at 3 o'clock integrated into the overall symmetry.

The integrated steel bracelet, with its alternating brushed and polished links, flows directly from the case in the seamless construction that was as radical in 1972 as it remains influential today.

A Royal Oak in its more intimate proportions — the original idea, undiluted.