The Watch Too Small to Ignore: Inside Audemars Piguet's Rarest Royal Oak

There's a version of the Royal Oak most watch people have never seen. It doesn't show up next to the Jumbos and Offshores at auction previews, and next to a coin, it would barely win.

It's 20 millimeters across, covered almost entirely in diamonds, with four small emeralds set as hour markers, on a piece dated 2005 and carrying the reference 67173BC. To understand why it matters, you have to go back to the watch it came from, and the year AP decided going small could be as radical as going big.

Steel, a Sketch, and a Crisis

The Royal Oak exists because of a crisis. In the early 1970s, the Swiss watch industry was staring down the quartz revolution, and Audemars Piguet needed something drastic.

What it got was Gérald Genta, reportedly sketching an entire watch the night before Baselworld. What came out was absurd for 1972: a luxury watch made of steel, with an octagonal bezel held down by eight visible screws, an integrated bracelet, and a tapisserie dial that caught light like nothing else on the market. It broke every rule of what luxury was supposed to look like  and it worked. The Royal Oak didn't just save Audemars Piguet, it invented a category.

That's the watch everyone knows. The Mini is that design pushed to its physical limit.

Shrinking an Icon, Then Going Further

Getting the Royal Oak smaller was its own engineering problem. A 1976 attempt at 29mm was about as small as automatic mechanics could go, so AP turned to quartz, shrinking the case further to 26mm in 1980 and 24.5mm in 1986.

Then came 1997, the 25th anniversary, and AP released the two most extreme watches the line would ever produce, at once. On one end sat the 44mm Grande Complication, still the largest Royal Oak ever made. On the other sat something that could hide behind it entirely: the Royal Oak Mini, reference 67075, just 20mm wide, built around an ultra-compact Jaeger-LeCoultre quartz movement barely over a centimeter across. It kept every visual cue of the full-size Royal Oak, shrunk into something you could lose in a coat pocket.

AP kept going, producing 26 versions of the Mini Oak over two years before quietly stopping in 1999. The entire run adds up to just 1,965 documented watches, and 23 of those versions were made in single digits or as one-off pieces of heavily gem-set, hidden-dial "secret" watches, built only because a client asked. Then the Mini Oak vanished for two decades, not returning until a 2024 revival in a slightly larger case.

           

A Piece That Went Further Still

Somewhere in that thin slice of rare production sits the 67173BC, near the far edge of what AP ever attempted at this scale. It isn't a Mini Oak with a diamond bezel bolted onto an otherwise plain watch, the more common treatment for the line. This one goes all the way: an 18-karat white gold case fully set with diamonds, a pavé diamond dial, and a diamond-set integrated bracelet, with four emeralds as hour markers.

The dealer listing dates it to 2005, several years after AP's records show the Mini Oak window closing in 1999  most likely a special commission built on the platform after the line's official run ended. AP hasn't published an exact count of 67173BC examples; given the gem-setting, it likely sits in "single digits, maybe unique" territory, an informed read rather than a confirmed figure.

             

Why It's Worth Writing About

Royal Oak collecting gravitates toward the loud references  steel Jumbos, Offshores, chronographs. The Mini Oak sits outside that conversation, which is what makes it worth writing about: a watch built at the height of AP's creative confidence, shrunk to a size no automatic movement could handle, dressed in more diamonds than most collectors will ever see in one place, then quietly forgotten. That's exactly the kind of watch worth pulling back into the light.