A moon phase display on a small watch is the most quietly ambitious thing Patek Philippe does at this end of the collection. The complication is not difficult in the way a repeater is difficult, but it is unusually easy to get wrong visually, because the aperture has to be cut into the dial at a size that leaves the disc legible without the opening dominating a face that is only 33 mm across to begin with. This reference solves that with a sunburst blue dial and a small aperture placed low on the display, so the moon reads as an incident on the dial rather than as the subject of it. The case is white gold with a diamond-set bezel and the reference runs to 2028. Small watches with real complications have become scarce across the industry, and the ones that survive tend to be inherited designs rather than current ones. This reference is neither. It was drawn recently for a modern audience and sized deliberately rather than by tradition, which is a different proposition from a vintage-sized watch offered as a nod to the past.
The case measures 33 mm across and 8.35 mm thick, which makes it one of the smallest complicated watches in the collection and the only one at this diameter to carry an astronomical indication. The bezel is set with diamonds and the case back is sapphire crystal, which is worth noting on a watch this size since a small movement seen through a proportionally large aperture appears more finished than a large one does. The dial is sunburst blue, a finish that shifts continuously as the wrist turns and reads nearly black at some angles and bright at others, which gives a simple dial far more life than a flat colour would. White gold applied Breguet numerals stand on it, and Breguet figures are the correct choice at this scale because they are drawn open rather than solid and take less of a small dial than applied batons would. White gold pear-shaped hands cross the display. The watch is worn on an alligator strap rather than a bracelet. A sunburst finish also behaves differently on a small dial than on a large one. The brushing radiates from the centre, so on a compact dial the rays are shorter and the transition from light to dark happens across less distance, which makes the effect more concentrated and more obvious as the wrist turns than the same finish would be at 40 mm.
The complication set is moon phases and small seconds, and the moon display is the reason the reference exists. A moon phase disc carries two moons and advances one tooth a day, showing the correct phase through the aperture as the disc turns, and the accuracy of the arrangement depends entirely on the tooth count chosen for the wheel that drives it. Patek Philippe uses a gearing that keeps the display correct to within a day over a period measured in decades rather than years, which is why a moon phase on a watch of this class is a different proposition from the same complication on a lesser one. Small seconds sits alongside it as the only other indication. There is no date, which on a dial this size is the correct decision, since a date aperture and a moon aperture competing on a 33 mm face would leave neither with room to be read properly. The placement of the moon aperture matters as much as its size. Sitting low on the dial rather than near the centre keeps it clear of the hands at every position they can occupy, so the display is never partly obscured, which is a common failing on watches where a moon window sits under the path of the hour hand.
Within the current selection this is the smallest complicated wristwatch and the only reference carrying a moon phase as its principal function rather than as an element of a calendar. Elsewhere the moon appears inside perpetual and annual calendar displays on the 5271P-010, the 5374 references and the 5961R-010, always as one indication among several. Here it stands alone. The 7300/1200R-001 in the Twenty~4 collection is the closest reference in size and audience at 36 mm with a set bezel, but it carries only a date. That leaves this reference occupying a narrow position, a small dress watch with a genuine complication and a jewelled bezel, which is a combination the collection offers in very few places. The reference also illustrates a division in how the collection handles the moon. Inside a calendar it functions as data, one indication among several to be read alongside the date and the month. Standing alone it functions as an image, something to be looked at rather than consulted, and the same disc serves an entirely different purpose depending on what surrounds it. That is a useful way to think about the reference generally, since almost everything on this dial has been decided by what was left out rather than by what was added.
The buyer for this reference wants a complication without a large watch, and that is a harder request to satisfy than it sounds. Most complicated references are built at 40 mm or above because the mechanisms and the displays both favour it, which leaves collectors who wear smaller watches choosing between size and content. This reference refuses that trade. The moon phase also happens to be the complication that most people find agreeable rather than impressive, since it does something visible and poetic rather than something technical, and on a small blue dial the effect is closer to jewellery than to instrumentation. Buyers tend to be people buying a dress watch who did not want it to be entirely plain. The reference entered the catalogue in 2022 and runs to 2028.
