News · Patek Philippe

Patek Philippe answers the Cubitus argument with a skeletonised perpetual calendar

The first grand complication in the collection puts a 27-jewel skeleton perpetual calendar into 10 mm of platinum, listed at US$187,547.

Hen & Mills Editorial · 4 min read · 18 August 2026

• Patek Philippe has given the Cubitus collection its first grand complication, a skeletonised self-winding perpetual calendar in platinum.
• Its openworked blue dial is cut as fine horizontal strips rather than conventional lacework, showing the movement through the gaps between them.
• Reference 5840P-001 measures 45 mm on the diagonal and 10 mm thick, on a navy composite strap, and Patek lists it at US$187,547.

Nobody was neutral about the Cubitus, which is the point of it

When Patek Philippe introduced a squared-off sports watch a couple of years back, the reaction split along a line you could have drawn in advance: half the room saw a Nautilus that had been sat on, and the other half pointed out that Patek has been making cushion and square cases since long before anyone thought integrated bracelets were a genre. What both halves agreed on was that it was a three-hand watch carrying an enormous amount of expectation. That expectation is now being answered, because the Cubitus has its first grand complication, the Perpetual Calendar Skeleton reference 5840P-001.

Putting a perpetual calendar into a case that people are still arguing about is a confident move. Skeletonising it as well is close to provocative, because an openworked dial removes the one thing a divisive case shape could hide behind, which is a calm dial to look at instead.

An openworked blue dial that behaves like a set of blinds

The dial is sunburst blue and openworked with a horizontal line pattern, and the way it works is more interesting than a photograph suggests. Rather than cutting the dial away into the usual lacework, Patek has laid down a series of fine strips across the face, so the movement shows through the gaps between them like light through half-closed venetian blinds. The result gives depth without the visual chaos that skeleton dials usually accept as the cost of doing business.

The perpetual calendar indications sit in blue subdials that read as solid against those strips, and the applied hour markers and hands are white gold with a luminescent coating. Moving in from the edge, you get day and 24-hour at one register, month and leap year at another, and a date-and-moon-phase display that is doing two jobs in one aperture. Everything is by hand rather than by window, which is the traditional Patek grammar for this complication.

Forty-five millimetres, ten millimetres, and platinum

The case measures 45 mm on its diagonal, from ten o'clock to four o'clock, and is 10 mm thick. Those two numbers together are the whole story of how this wears: 45 mm sounds enormous until you remember it is a corner-to-corner measurement on a squared case, and 10 mm on a perpetual calendar with an automatic movement is genuinely thin.

It is made in platinum, which Patek marks in its usual way with a baguette-cut diamond set into the case at six o'clock. Platinum is the heaviest of the case metals in normal use and it will make this watch feel substantially more serious on the wrist than the dimensions suggest, in the way a platinum watch always does, which is a large part of why people buy them. Water resistance is 30 metres, so this is a watch for a dinner rather than a swim.

Twenty-seven jewels, three hertz, and a reserve that asks something of you

The movement is the calibre 28-28 Q SQU, self-winding, skeletonised, with 27 jewels and running at 21,600 semi-oscillations per hour, or 3 Hz. Patek quotes a power reserve of between 38 and 48 hours depending on state of wind. That is a short reserve by any modern standard, and on a perpetual calendar it is the one specification worth thinking hard about, because a stopped perpetual calendar is not a watch you simply reset.

Two days is enough to carry it overnight and through a weekend day, and not enough to leave it in a safe from Friday to Monday without consequence. This is a watch that wants a winder or a routine, and anyone spending this much will have already worked that out. Turn it over and a sapphire caseback shows the shaped movement and its openworked bridges, with the micro-rotor doing the work.

Navy composite, which is a genuinely modern choice at this price

The strap is a navy blue composite with a fabric pattern, closed with a platinum fold-over clasp. A composite strap on a platinum grand complication would have been unthinkable a decade ago, and it is the detail that tells you who Patek thinks is buying this: somebody who wants a perpetual calendar they can wear with an open collar. It is also, practically speaking, a material that will survive a summer better than alligator.

For a collection that arrived to a chorus of doubt, this is a reasonable answer. Not an argument about whether the case shape works, just the most demanding thing Patek makes, installed in it, and left visible.

Patek Philippe Cubitus Perpetual Calendar Skeleton pricing and availability

The Cubitus Perpetual Calendar Skeleton is reference 5840P-001, in platinum on a navy blue composite strap with a platinum fold-over clasp. Patek Philippe lists it at US$187,547. No Australian price is published on the brand's site, and distribution runs through Patek Philippe authorised retailers.