As Lange & Söhne rightly claim of its innovative Lange Double Split, ‘a new era of chronography has begun.’ The intricate complication of a ratrappante sweep-seconds hand in a chronograph has always been considered as a remarkable accomplishment for short time measurements, however, it had its limitations since readings were limited to the 60-second scale and therefore measurements of less than one minute.
The principle of the ratrappante sweep-seconds hand has now been extended to the jumping minute counter, making time measurements of up to 30 minutes now possible with a purely mechanical watch. Additionally, the chrono sweep-seconds hand continues its rotation whilst the ratrappante sweep-seconds hand is stopped because of a disengagement mechanism Lange has specially developed.



The functions
With its manually wound Calibre L001.1 movement, the Lange Double Split indicates the hours and minutes on its two-tiered black and silver dial, the seconds on its silver subsidiary dial between 8 and 9 o’clock, with a power reserve indicator with a red hand at 12 o’clock. The small-seconds dial and 30-minute counter of the chronograph are between 3 and 4 o’clock.
The chronograph function is activated by the start/stop push piece that sets off the fine gold-plated chrono sweep-seconds hand – the ‘watch in the watch’ concept. By re-activating the push piece, the hand stops. When the zero reset push piece at 4 o’clock is activated, the sweep-seconds hand returns to the 12 o’clock position.
Each time the chrono sweep-seconds hand crosses the 12 o’clock marker, the gold chrono minute counter jumps by one minute. Whilst the chronograph mechanism is working, both the chronograph hands can be instantly re-set to zero by pressing the push piece at 4 o’clock and when it is released, the chrono sweep-seconds hand restarts immediately and the minute counter will advance by jumping one minute later. This flyback device makes it possible to in-itiate a new measurement instantly – as opposed to the standard chronograph when the hands have to return to the zero position. The flyback mechanism puts all these interventions into one actuation.
Now for the ‘watch in the watch in the watch’. The rattrapante sweep-seconds hand in steel, is situated above the chrono sweep-seconds hand. During an on-going time measurement, the ratrappante hands can be used for a separate measurement at any given moment. When the start/stop push piece at 2 o’clock is pressed, both pairs of hands are set in motion immediately. The ratrappante push piece at 10 o’clock is pressed to measure the first time. The ratrappante sweep-seconds hand stops instantly, displaying the measured time. For the second measurement, the start/stop push piece is pressed to stop the chrono sweep-seconds hand that is still rotating, thus enabling the reading of a second time as a separate result or a comparison to the first measurement.
For more than two consecutive measurements after the hands have been set in motion, the first time, stopped by the rattrapante push piece at 4 o’clock, must be noted. The renewed activation of the push piece causes the rattrapante sweep-seconds hand to instantly catch up with the still-running chrono sweep-seconds hand. This process can be repeated as often as wished as long as the chrono sweep-seconds hand is in motion and the aggregate time measurement has not been interrupted.
The Lange Double Split has a chrono minute counter as well as a rattrapante minute counter making the rattrapante time measuring range not just 60 seconds as with conventional chronographs, but 30 minutes. This was achieved by duplicating the construction of the chrono/rattrapante wheel pair – i.e. the minute-counter wheel has a through bore that accommodates the shaft of the second rattrapante wheel. Since the watch contains a chronograph mechanism with a jumping minute counter, the rattrapante minute-counter also jumps.
The extraordinary mechanisms of the Lange Double Split offers comparative times by storing time measurements and resetting the chrono sweep-seconds hand. To compare times – for example lap times – the first lap is stopped with the pair of rattrapante hands and the second time with the chronograph hands.
If the lap time displayed by the chronograph hand is the shorter of the two, this can be stored as the minimum by pressing the rattrapante push piece twice. The first actuation causes the rattrapante hands to line up with the chronograph hands, the second actuation freezes them. If the lap time indicated by the rattrapante hands is shorter, no action is required, the hands stay where they are. The next lap can then be timed by re-setting, re-starting and re-stopping the chronograph hands.
To determine the slowest lap, the rattrapante push piece must be pressed twice if the time measured by the chronograph hands is greater. In both cases, the time displayed by the rattrapante hands at the end of a series of time measurements is the extreme (maximum or minimum) of all stopped times.
Lange & Söhne has created an extraordinarily innovative wristwatch that simplifies complex timing and it will surely create all sorts of emotions amongst connoisseurs and time fanatics. And if you think reading about the watch appears complicated, try writing about it!

Photo: LANGE DOUBLE SPLIT
43 mm platinum case, sapphire crystals front and back, silver two-tiered dial, 40 jewels, lever escapement, shock-proof Glucydur balance with regulating cams, Nivarox 1 balance spring with balance spring clamp, frequency of 21,600 semi-oscillations per hour, 38-hour power reserve, crown for winding and time setting, two push pieces for operating the chronograph, one push piece for operating the rattrapante, cumulative and lap-time measurements between 1/6th of a second and 30 minutes.