The chronograph is widely regarded as one of the most useful complications. But for purists, there is a world of difference between a chronograph “complication” where a chronograph module has simply been added to an existing mechanical calibre and an integrated chronograph, where the function is incorporated within the base calibre (and has the added bonus of keeping the movement, and therefore the watch, much thinner).

There is a much wider gulf still, however, between these integrated chronographs and the Breguet Tradition Chronographe Indépendant 7077. In this timepiece, the timekeeping mechanism and chronograph mechanism have been dissociated, each having their own independent going train with a separate balance spring and escapement. The timekeeping mechanism operates at a frequency of 3Hz and offers a power reserve of 50 hours. The chronograph mechanism, on the other hand, operates at a faster 5Hz and runs for just 20 minutes.

Breguet Tradition Chronographe Independant 7077. © Breguet

Here are four things that set it apart from other chronographs:
1) The blade spring
The reason for this unusually short power reserve is the use of a blade spring instead of a separate sprung barrel to power the chronograph. Inspired by the Breguet No. 4009 watch of 1825, this technology offers a number of advantages. Not only is it perfect for measuring short elapsed times, it also allows the chronograph to be started instantly, immediately setting the balance wheel into motion at the correct amplitude.

2) A patented balance wheel
Notice how the two visible balance wheels are the same size, even though they oscillate at different frequencies? In order to keep the chronograph balance wheel the same size as the one for the timekeeping, it has been made in lightweight titanium (if it was made of the same material as the balance wheel used for timekeeping it would have to be smaller). It is a Breguet patent that meets an important aesthetic requirement, since one of the main features of the Tradition collection is that the principal movement components should all be visible.

The two visible balance wheels are the same size, even though they oscillate at different frequencies. © Breguet

3) Rewind on reset
Unlike other chronographs, which have a start/stop button and a separate reset button, the Breguet Tradition Chronographe Indépendant 7077 has a button for the start and one for the stop and reset functions. Ingeniously, the simple action of pushing the reset button is enough to arm the blade spring with 20 minutes of power reserve ready for the next time the chronograph function is activated.

4) Unrivalled precision
Much attention is focused on the precision of a watch but very little on the precision of a chronograph. What is the point of having a chronograph accurate to 1/10th of a second if the balance wheel powering it can never hope to reflect this accuracy in actual use? Using its unique configuration, which also includes a non-concentric gear train assembly that ensures a constant amplitude of the balance wheel, Breguet achieves an astonishing precision of +/- 0.04 second over the 20-minute power reserve of the chronograph.

Beautiful symmetry as a bonus
In addition to the considerable technical achievements made by Breguet with the Tradition Chronographe Indépendant 7077, the beauty of the dial should not be overlooked. Against a sober grained dark background of the mainplate and bridges, the offcentred 18-carat gold, engine-turned dial is the focus of a totally symmetrical arrangement: sectors on either side of the dial show the power reserve for the chronograph and the time display respectively and underneath the two balance wheels and escapement are also arranged symmetrically. There are just two subtle differences between the two arrangements: a black surface treatment to the chronograph balance wheel and an inversion of the two escapements. This rare aesthetic exception is for the benefit of the watchmakers, who need to be able to tell the two balance wheels and escapements apart when assembling the watch.

The engine-turned dial in silvered gold showing the hours and minutes is offset at 12 o'clock. © Breguet

The Breguet Tradition Chronographe Indépendant 7077 is available in 18 carat white gold or 18-carat rose gold with a leather strap and costs 77,000 Swiss francs.