Tech Talk: Montblanc’s TimeWriter II Chronographe Bi-Fréquence 1000

Montblanc TimeWriter II Bi-Frequence sideIf three watches constitute a trend, then measuring milliseconds, or 1/1,000s of a second, is a trend. Two watch brands, each with high-speed horological histories, have launched mechanical chronographs claimed to be capable of accurately measuring 1/1,000s of a second. Last year, TAG Heuer debuted its Mikrotimer Flying 1000 Concept Chronograph, followed this year by the even faster Mikrogirder. At SIHH this year, Montblanc launched its own millisecond-measuring marvel, the TimeWriter II Chronograph Bi-Fréquence 1000, which employs a unique approach to splitting seconds.

In a sense, development of Montblanc’s high-speed chronograph began in 1916. That’s when Minerva launched its first 1/100s-of-a-second stopwatch. Acquired by Richemont in 2006, Minerva was a true manufacture, known for chronographs and pilots’ watches. In 2007, Richemont decided that Minerva would produce movements for Montblanc, and the following year, Montblanc launched the “Fondation Minerva” to create the TimeWriter series, consisting of extraordinary timepieces developed with  independent watchmakers. The first piece in the series – Metamorphosis – was launched in 2010. The newest piece, the Bi-Fréquence 1000, is the latest TimeWriter creation.

Because of Minerva’s long experience producing high-speed chronographs, Montblanc recognized that constructing a chronograph capable of measuring 1/1,000s of a second over a useful interval presented four challenges:

1. The movement must be precise, and simply increasing the frequency of the balance wheel would not work, because engaging the chronograph would cause a significant loss of amplitude, reducing precision.

2. A gear train that advanced 1,000 times per second would be subjected to wear and tear that would reduce the movement’s longevity.

3. The chronograph indications must be legible. Measuring to the nearest 1/1,000s of a second means nothing if the elapsed time to the third decimal cannot be easily read.

4. The chronograph must be useable in the real world, meaning it must be able to measure intervals longer than just a few minutes.

(Click on watch photos for larger images.)

Montblanc TimeWriter II Bi-Frequence side

To meet these challenges, Montblanc  teamed up with independent watchmaker Bartomeu Gomila, who had an ingenious idea for measuring 1/1,000s of a second. Gomila’s concept was based on a childhood toy – a simple hoop kept rolling with regular taps from a stick. The result is a chronograph with a unique system for splitting seconds into ever-smaller units, and an unusual way of displaying those units.

Any discussion of the Bi-Fréquence must begin with an overview of the dial layout. At first glance, an observer might note that Montblanc has failed to satisfy its self-imposed legibility requirement. In an interview, Montblanc’s managing director of watches, Alexander Schmiedt, acknowledged that the Bi-Fréquence is “not an easy watch.” However, as we learned firsthand, a brief orientation yields an understanding of, and even an appreciation for, the dial’s clarity.

As shown in the photos, the time of day is displayed by the small, white, center-mounted hour and minute hands. The chronograph is a monopusher design, with the start, stop and reset functions controlled by the single pusher located between the lugs at 12 o’clock. The pusher’s location is a nod to the early Minerva 1/100s-of-a-second stopwatches.

The chronograph elapsed seconds and minutes are displayed co-axially at 6 o’clock. The longer, red-tipped hand displays 60 elapsed seconds on the white outer track, and the shorter solid red hand displays elapsed minutes on the red inner track. The 1/100s of a second are indicated by the center-mounted red hand with arrow tip. This hand makes one trip around the dial per second, displaying the 1/100s of a second increments clearly. The 1/1,000s-of-a-second display is located in a large, curved window at 12 o’clock. Inside the window, the letter “N” and the numerals 0 to 9 indicate the status of the display and denominate 1/1,000s of a second. When the chronograph is running, the small, red, triangle-shaped indicator at the bottom of the window remains motionless, pointing to the red “N.” At the moment the chronograph is stopped, the red arrow instantly jumps to indicate the elapsed 1/1,000s of a second. Putting all of these chronograph indications together, in the image below, the total elapsed time is 2 minutes and 19.139 seconds.

The chronograph has its own mainspring barrel, the power reserve of which is visible on the dial at 3 o’clock. The winding crown is bi-directional; turning it one way winds the timekeeping mainspring and the other winds the chronograph spring barrel. The chronograph’s autonomy is 45 minutes when fully charged, and the reserve can be increased by winding the crown while the chronograph is running. Montblanc says the chronograph’s long power reserve helps maintain the balance wheel’s amplitude, which increases timekeeping precision. Another interesting feature: the chronograph escapement has its own regulator, which is visible in the image of the movement through the caseback.

Montblanc TimeWriter II Bi-Frequence front

Map of MB Bi-Frequence dial

Now that we comprehend the dial, we can discuss what lies behind it. Or at least we can discuss what we know, because Montblanc has not yet fully revealed all of the technical details.


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About Mike Disher

My name is Mike Disher and I am WatchTime's technical editor. My interest in watches dates to 1972 and I caught the internet bug in 1997. In 1999 I combined these interests by joining as its first full-time employee, and later that year I attended my first Basel Fair. I managed TZ from 2000-2007, and in 2008 I joined WatchTime.


  1. MrTissot says:

    This is a truly amazing piece of horological art. It;s just a shame that the dial is soooooooo busy!

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