Edouard Koehn launches the Legacy Rattrapante split-seconds chronograph

0 0 Wednesday 25 September 2024 Edit this post

Swiss watch brand Edouard Koehn is launching today the Legacy Rattrapante, a split-seconds chronograph enriched by a precious Grand Feu enamel dial.

Highly appreciated by connoisseurs, this sophisticated complication was often featured in the production of Edouard Koehn (1839-1908), a recognised master in crafting these complex mechanisms.

Unlike a standard chronograph, the split-seconds, or rattrapante, chronograph has two hands that start simultaneously. The rattrapante hand, which is superimposed on the stopwatch hand, can be stopped independently using a third push-button, while the stopwatch hand continues to run. This permits the user to measure intermediate times. If the third button is pushed again, the split-seconds hand instantaneously catches up (rattraper in French) and is synchronised with the other hand.

The Legacy Rattrapante is housed in a 316L stainless steel case, featuring two rectangular pushers positioned at 2 o’clock and 4 o’clock to start/stop and reset the chronograph, respectively. A third pusher, coaxial with the crown, controls the split-seconds function.

Characterised by classical lines and polished surfaces, the round case measures 40 mm in diameter and 14.60 mm in thickness, including the double-sided antireflective glass box sapphire crystal (or 13.10 mm without it).

The dial faithfully reproduces the layout used in a split-seconds pocket watch produced by the brand in the early 1900s.

Edouard Koehn 1900’s split-seconds chronograph

The instantaneous 60-minute chronograph counter is positioned at 12 o’clock and visually balanced by the small seconds sub-dial at 6 o’clock.

Two second-hands are positioned one above the other: the red hand runs continually whenever the chronograph function is active; below it, the blue one can be momentarily halted at the push of the crown-coaxial button.

The dial’s appeal is further enhanced by the centuries-old Grand Feu enamel technique, which imparts a luminous texture that will retain its vibrancy and radiance over time.

This traditional process, used by watchmakers since the 15th century, involves meticulously applying enamel powder—a blend of silica, metallic oxides, and potassium—onto the dial’s base plate. The two are then fused together by firing them at an intense 840 degrees Celsius (1,544 degrees Fahrenheit).

The name "Grand Feu" refers to the high temperatures required to melt the enamel, ensuring its exceptional durability and rich, long-lasting colour.

Finally, the Breguet numerals and the inscriptions on the dial are transferred onto the enamel surface and fused together by the final firing.

The outer minute track is split by four divisions, in accordance with the 4 Hz (28,800 vibrations per hour) frequency of the movement powering the watch. This way, when you stop the chronograph seconds hand, the read-out is more accurate.

Visible through the transparent sapphire crystal caseback, the self-winding chronograph calibre is developed in collaboration with Concepto, an independent manufacturer known for producing high-end mechanical movements.

Comprising 282 components, this movement features a chronometer-grade regulating organ and delivers a 48-hour power reserve.

Its finishesg include perlage, blued screws, solarised wheels, and Geneva stripes on the ball-bearing-mounted central rotor.

Paired with a black Louisiana alligator leather strap with a stainless steel folding buckle, the new Edouard Koehn Legacy Rattrapante, ref. EK-CHR11SS-SL-WEEL-ASBK, is a limited edition of 50 individually numbered pieces (XX/50) with a retail price of CHF 15,800. edouardkoehn.com