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A brief explanation of a major complication #4: The Chronograph & its scales

Anna Wu-Chauvineau
Le 13 March 2017

With the previous “explanations” we got you used to the heavyweights of the world of complications such as the tourbillon, the perpetual calendar, and the minute repeater. Today, we’re going back to the roots with a complication much more common, but with a multitude of uses and scales: the Chronograph.

Please note that we’re talking about the chronograph or chronoscope, and not the chronometer, too often wrongly used.

A friendly reminder:

Chronometer (noun):
Certification delivered by the COSC (Contrôle Officiel Suisse des Chronomètres), to watches having passed the series of quality and performance tests.

Ed. note: There’s a fee for this Swiss certification, of course. This does not mean that watches not certified COSC, often German or Japanese operating by their own standards (Glashütte Observatory or Grand Seiko for example), don’t meet or exceed their standards. Thank goodness for them.

Now back to the chronograph…

Auricoste Type XX - Detail

The Chronograph

Chronograph, noun:
An instrument for measuring and recording time intervals.

In general the process is activated by a pusher located on the side of the case to start, stop or reset the counter.

In terms of measuring time, several combinations are possible. Traditionally we have a long central seconds hand, two sub-dials that measure and totalize the hours, the minutes, but also the quarter hours, the tenth hours and so forth.

Easy right? Let’s go deeper shall we?

There are different complications in the world of the chronograph. Our favorite ones are:

The Flyback chronograph allows you to use the reset function without the need to first stop the chronograph (usually by pressing the reset pusher), and the split-second chronograph that has a second hand to measure intermediary time, also able to “catch up” to the first hand of the chronograph in order to time different events that begin but do not end together. Very cool wouldn’t you agree?

But it doesn’t stop here. Depending on the printed, painted or stamped graduation on the dial, the internal upper ring, or the bezel, the chronograph complication can allow the instant measure of other elements besides time.

The different scales

We’ve decided to keep it simple today because some scales need an entire article dedicated to them alone given the complexity of their function.


The tachymetric scale allows you to measure the rate of a vehicle in movement, and the traveled distance by it if we know its rate. Remember Distance = rate x time.


A doctor’s watch par excellence, the pulsimeter allows you to measure the heart rate in much less time than a whole minute (15, 30 or 45 beats depending on the graduation). When every second counts, it can make all the difference.


Heuer Calibre 72

Less common and not often used today, the decimal scale that we find on the dial of this Heuer Caliber 72, was above all made for engineers needing to make numerous calculations of time or cost prices.

The minute is divided into 100 hundredth of a minute instead of 60 seconds in order to measure and translate time into decimal values, making calculations more convenient afterwards.

1.5 minutes = 1 minute and 30 seconds
1.75 minutes = 1 minute and 45 seconds
1.5 + 1.75 = 3.25 minutes or 3 minutes and 1/4 minute or 3 minutes and 15 seconds


Here’s a fun fact, the telemetric chronograph was developed for officers during WWI in order to quickly know the distance of enemy troops when they began attacking the trenches. The officer only needed to trigger the chronograph when canons were fired (by sight) and stop at the sound of the detonation. The telemetric scale indicated the distance of enemy troops, translated in kilometers or in miles depending on the graduation.

If most of us are lucky enough to not have known the war in the trenches, a telemetric chronograph does not become useless. You can explain to your little nephew the D = rt relationship by a stormy night in calculating very precisely and very easily from what distance did thunder strike.

So? A “simple” chronograph you say? More like one of the most useful complications that exist and also for various daily life functions!

A sure and elegant way to respect the ideal infusion time for that “perfect cup” of Earl Grey (3 minutes at 85°C) or the strong-bodied Italian coffee blend in your French Press (4 minutes). A superb way to start the day I reckon. Gentlemen, to your kettles!