Still very much in the throes of the quartz crisis, complicated watchmaking was hard to come by as brands struggled merely to survive. However, it was in the middle of this, in the late 1970s, that intrepid watchmakers at Audemars Piguet worked in secrecy, modifying the calibre 2120, to create what would become the world’s thinnest self-winding perpetual calendar. When presented with the finished product, Georges Golay, the brand’s chief executive officer and the man who had green-lit the Royal Oak a few years prior, decided to take yet another risk and put it into production. The Quantième Perpetuel, mated to the now iconic stepped bezel case designed by Jacqueline Dimier, went into production in 1978 and is widely credited with seeing the brand through this period of crisis.

While several references were in production simultaneously, the reference 25657 was part of the brand’s catalogue between 1982 and 1993, making it one of the earliest. This is one of the 128 examples that were forged from platinum, and features all the hallmarks, including the recessed subsidiary registers. The white metal case serves to further accentuate what is already a remarkably striking ‘Tuscan’ blue dial. It wears a granular texture that gives the blue dial added depth. The outer chapter, as well as the subsidiary registers feature a smooth texture. While the hour markers are applied, the outer chapter is printed in white, as are the scales on the subsidiary registers. They feature simple, stick hands, same as the ones indicating the hours and minutes.

The register at 12 o’clock indicates the month of the year while the ones at 3 and 9 o’clock display the date and day of the week respectively. The register at 6 o’clock features the moonphase, with the brand mark and the word ‘Automatic’ printed on.

While the reference is one of the earliest, the case on this particular watch features a number of design improvements that came later in the series’ run. This includes a flatter stepped bezel and caseback, that had been redesigned to improve water resistance. These changes also included better protected correctors. All this translates to a flatter overall case profile which makes this watch more comfortable on the wrist.

This Quantieme Perpetual features the calibre 2120/2, derived from Jaeger-LeCoultre’s legendary ultra-thin JLC 920 calibre movement, a movement whose development Audemars Piguet funded in part. The ultra-thin automatic calibre features 38 jewels, Gyromax balance and four ruby wheels to support the full-diameter rotor, which runs on a beryllium rail for stability. The rotor is decorated with Geneva stripes and edged with 21-carat gold, to increase the oscillating mass.

This watch comes with an Audemars Piguet leather folio style box and unstamped, undated papers.

If sold within the United Kingdom, this Audemars Piguet Quantième Perpétuel will be subject to 20% VAT

Closer look

Condition

This platinum Audemars Piguet Quantième Perpétuel is in very good condition, showing small signs of its age throughout. The case is nicely preserved, retaining a pronounced step in the bezel which has some superficial marks and a small ding at 6 o'clock. The rest of the case is also very good, showing the correct finishing styles and remaining sharp. This includes the engravings and hallmarks on the caseback, which are crisp and well-defined. The dial shows some small marks consistent with the age of the watch, while the hands show no notable marks when examined under a 10x loupe. The accompanying materials are in good overall condition. Included in the set is a green leather folio style AP box and a "Certificate of Origin and Guarantee" booklet, which serves as the paperwork. The latter has the serial numbers filled in with handwriting and doesn't feature a retailer's stamp, signature or sale date.

Warranty

The watch comes with a two-year warranty from A Collected Man, alongside a lifetime guarantee of authenticity.