What do the dials on a chronograph watch do?
To be able to explain the 3 subdials (also known as auxiliary dials) and their functions, we need to first clarify what a chronograph watch is: a timepiece that can be used as a stopwatch in addition to its standard display watch capabilities.
In watch experts language, chronographs fall under the umbrella of complications – watches that perform more than one function.
Some of the most well-known chronograph in the modern watch world are the Rolex Daytona, the Omega Speedmaster or the Zenith El Primero: chronographs are the eternal collector’s favorite and especially in these last few years they have been experiencing an unprecedented boom in the collector community.
Let's start explaining which elements you can find on this type of watch's dial:
A. The date window, usually located either at 3 o'clock, between 4 and 5 o'clock or at 6 o'clock, shows in which day of the month we are. The 3 o’clock date is undoubtedly the most common date position in the history of date windows on dials. It was made popular by Rolex’s 1945 Datejust and it has become an evergreen design ever since.
This date window is commonly paired with a cyclops lens designed nine years after the release because Hans Wilsdorf's (the founder of Rolex) wife couldn’t read the date without her glasses
B. The second hand subdial also called sub-seconds: usually in high range chronometer watches the hand of the seconds is stopped and not moving. The seconds function is instead displayed in one of the little dials, usually the one with the 20-40-60 numbers.
You can find this subdial also in many watches that are not chronograph, for a pure aesthetic choice.
So what do we need the hand of the seconds (C.) for?
In chronograph watch, pushing the top button on the crown at 2 o'clock (D.), the second hand will start to move and it can be used as a chronometer.
At this point you are enjoying this fantastic function of your watch, but a doubt arises in your mind: after activating the chronometer, how do we know how many minutes, or even hours, have passed?
This is when we need the other 2 of the 3 little dials!
E. The minute counter subdial: after activating the chronometer, it will tell you how many minutes have passed. Many times it will reach the 30 minutes, instead of 60, just to give more visibility to the result.
However if you use the hour subdial, it is easy to understand if the 30 minutes that you are counting are the "first" 30 minutes of an hour (so from minute 1 to minute 30), or the "second" minutes (do from minute 31 to minute 60).
F. The hour counter subdial: after activating the chronometer, it will tell you how many hours have passed. It arrives to a total of 12, so this is usually the maximum chronometer capacity of luxury watches.
How to set them back to 0? Very simple! If we start the chronograph by pressing the button at 2 o’clock, we can stop the chronograph by pushing that button again. Instead, we can reset the chronograph by pushing the button at 4 o’clock (G.).
Many of these watches have a tachymeter on the bezel that is needed to measure speed over distance.
The ritual of timing, stopping and resetting to zero connects us to the past and to some of the most romantic functions of these watches. Also their visual presentation is something that sets them apart from other watches.
Now that you know what those 3 subdials are and how to read them, you are ready to "play" with one!