A Classic Moonphase is the complication that shows the current phase of the moon in a small window on the dial. The mechanics are simple and elegant: a disc painted with two moons is driven by a 59-tooth wheel that advances one tooth per day, mimicking the roughly 29.5-day synodic lunar cycle. Because the real lunar month runs 29 days, 12 hours and 44 minutes, a standard 59-tooth setup drifts about a day every two years and seven months. The complication descends from pocket watches and astronomical clocks; Patek Philippe fitted its first wristwatch moonphase in 1925, and Rolex launched reference 8171 in 1949. Today the classic form lives on as a gold moon waxing and waning across a star-flecked blue disc on a restrained dress dial.
The real models that define this category span a wide range. At the top, the Patek Philippe 5396 Annual Calendar Moonphase, 38.5mm, pairs an annual calendar with a high-precision moon accurate to a day in 122 years and retails near $64,000 in gold. The A. Lange & Söhne 1815 Moonphase, in its honey gold Homage to F.A. Lange limited edition, runs astronomical gearing accurate beyond a thousand years, while the catalog Lange 1 Moon Phase holds to 122.6 years. Breguet's Classique 7787, 39mm with the in-house calibre 591DRL, carries the guilloche tradition and runs roughly $28,000 to $37,000 in gold, more in platinum. In the middle, the Jaeger-LeCoultre Master Ultra Thin Moon in steel sits around $13,000 with that same 122-year accuracy. At entry level the in-house Frederique Constant Manufacture Moonphase delivers real value between $3,000 and $4,400, while Longines and the Christopher Ward C1 offer the same spirit affordably.
When buying, look first at dial balance and legibility: a classic moonphase should feel calm and unfussy, and the quality of the moon-disc finishing and night-sky tone tells you a great deal about the maker. If precision matters to you, seek the 135-tooth or astronomical calibers rated to 122 years or beyond, because a standard mechanism will need correcting every couple of years. Added functions like date, power reserve or an annual calendar crowd the dial, so decide how much restraint you want. The Classic Moonphase suits the buyer chasing a first proper complication, someone who values elegance over flash.
There are a few sub-flavors within the category. A pure moonphase shows only the lunar display, while combined references fold it into a date, day or full calendar. Dial techniques such as grand feu enamel or aventurine night skies turn the same complication into a hand-crafted object. Whichever interpretation you choose, the point of a classic moonphase is not to measure time precisely but to carry a piece of the sky on your wrist.