Chronograph (stopwatch), chronometer (precision certificate), tourbillon (an escapement to increase accuracy) and Geneva Waves (a traditional Swiss decoration technique): the horological dictionary is full of terminology that gets enthusiasts excited but may mean very little to outsiders. However, some expressions are self-explanatory, such as the subdials.

As their name suggests, these are small dials that display various functions across the main dial. The more complex the watch, the more of these subdials are needed. They are particularly common on calendar watches, which provide information on the current day of the week, month and date, such as the Vacheron Constantin Traditionelle Complete Calendar, shown above.

Other functions that are usually displayed on subdials are the power reserve indicator and the GMT indication. The moon-phase indication, one of the oldest and most charming complications, is also usually shown on a subdial. It has a particularly refined entrance on this Master Ultra Thin Tourbillon Moon by Jaeger-LeCoultre.

One special type of subdials are the so-called totalizers or counters, which indicate the elapsed minutes and hours on chronographs, like on this Seventies Chronograph Panorama Date by Glashütte Original.

However, a subdial does not necessarily have to be round, but can also echo the cushion shape of the case or displayed on a sector, which is often the case with retrograde displays, when a hand jumps back to zero before it starts its journey again, like on Maurice Lacroix’s Triple Rétrograde Masterpiece.

Despite its name, a subdial can also display the main time. This is called an off-centered time display.

One of the best-known examples is the Lange 1 from A. Lange & Söhne, whose harmonious layout with off-centered hours and minutes, power reserve display, large date and small seconds has written history in modern times.

Speaking of small seconds or subsidiary seconds, they are the most common function displayed on a subdial. In particular, it lends a nostalgic touch to classic three-hand timepieces, such as the above pictured The Longines Heritage Classic – Tuxedo.

Do you have a favorite subdial-equipped timepiece? Let us know in comments, below!