Following the presentation of its first perpetual calendar Royal Oak model in 1984, Audemars Piguet followed up with an openworked version in 1986 including a sapphire caseback. Reference 25636 was in production until 1997 and made in 60 pieces in steel, 156 pieces in yellow gold, 6 pieces in pink gold, 41 pieces in platinum, 24 pieces in pink gold and platinum, and 25 pieces in steel and platinum, for a total of 312 examples.

Exceptionally bold, the present Royal Oak Perpetual Calendar is offered in excellent condition with a visually arresting openwork dial and movement. The beholder is hypnotized by the breathtaking view of the movement from both front and back. Non-essential metal from the movement’s plates and bridges have been removed, while the remaining “openworked” parts have been delicately hand engraved and finished. One can see a symphony of foliage, chamfering, mirror polishing and sunray finishes.

The present reference 25636 is part of the last generation of openworked perpetual calendar models offered without a leap-year indicator, which would later be introduced on all subsequent Royal Oak perpetual calendar models by the mid-1990s. Highly sought-after by connoisseurs, these first generation models are appreciated for their simple and pure elegance.

One of just 60 pieces made in steel, the present watch will surely impress the most discerning collectors who are seeking for a splendid specimen of this coveted reference.