Podcast How Watches Work E6 – Complicated Chronographs – Flybacks, Split-Seconds, Ultra-Fast, & More

Allen and David continue their journey through the world of mechanical chronographs. In this episode of ‘How Watches Work’ they discuss flyback chronographs, rattrapante or double chronographs and the race to release the worlds first automatic chronographs.

The flyback chronograph is a common variant that combines the stop, reset and start functions into a single press of the reset button. The flyback functionality quickly found favor with aerial navigators with Longines quickly modifying its 13.33Z, recognized as the world’s first wrist watch chronograph, to create a flyback variant which eventually lead to Longines filing a patent for the flyback chronograph in 1936.

While the flyback chronograph might be quite common, our next chronograph variant is definitely not. The rattrapante, alternativekly known as the double or split chronograph, provides an extra button typically on the other side of the case at 10 o’clock. Pushing the extra button while the chronograph is running appears to split the second hand leaving one hand stationary while the other continues timing.

The hand does not actually split even though that is how it seems. A rattrapante chronograph has two sweep hands, stacked one on top of the other using coaxial arbors. Pressing the extra button stops one of those coaxial hands while the other continues running. Pressing the button again causes the stopped sweep hand to catch up, or rattraper in French and start rotating again in sync with the other sweep hand, again appearing as a single hand.

Temporarily stopping a hand while the other continues to measure elapsed time allows the user to record a ‘lap’ time without have to stop timing the entire ‘race’. As one can imagine, implanting this split second functionality, in a mechanical movement is quite complicated. Not only are there nearly twice the number of chronograph components crammed into a similar space, they have to interact with each other which adds to the complexity. For example the clutch needs to be able to decouple one hand to stop and clutch and be able to decouple two hands to reset both. 

This explains why rattrapante chronographs typically remain expensive high-horology complications typically available only from the grand maisons and when they are available they typically cost more than $10,000. One watchmaker that has worked to reduce the cost and complexity of the rattrapante is Richard Habring. While at IWC, he developed a double chronograph using two coupled ETA 7750 regular chronograph movements, significantly reducing the cost of the complication. Richard continues to develop this approach in his own branded Habring Doppel model.

The undisputed king of the rattrapante complication however is A. Lange & Söhne. Not satisfied with the base functionality of the rattrapante chronograph, A. Lange & Söhne released the ‘Double Split’ in 2004. This watch not only split the second hand when the additional pusher was activated, it also split the minute totalizer. This meant that split times up to 59 minutes and 59 seconds cod be separately recorded. In 2018, they released the ‘Saxonia Triple Split’ which split the seconds, minute and hour totalizer, allowing split timing to be recorded up to 12 hours in duration.

A Lange and Sohne caliber L132.1
The incredible complexity of the Triple Split’s caliber L132.1. Image credit: A. Lange & Söhne

Towards the end of the 1960 decade manufacturers were obsessing how to produce an automatically wound chronograph. Up until this time, all chronographs were manually would event though automatically wound wristwatch was almost as old as the chronograph, invented by John Harwood in 1923. It took until 1969 before the two wristwatch developments would coincide.

Zenith were first to announce an automatic chronograph movement in January 1969, named in an act of genius as ‘El Primero’ ensuring that in peoples’ minds, Zenith would always be associated with the first automatic chronograph. However, Zenith would not actually produce watches containing the El primero movement until December 1969 due to production and reliability difficulties.

At the same time as Zenith were working on their ambitious, fully integrated 36,000 vph high beat ‘El Primero’ capable of timing 1/10ths of a second, Dubois-Dupraz, the established manufacturer of chronograph add-on modules for regular ébauche movements, had teamed up with Breitling, Hamilton-Büren and Heuer to develop a modular automatic chronograph movement known as ‘Project 99’. Project 99 combined micro-rotor technology from Büren with a chronograph module from Dupraz. Caliber 11 as the movement became known was presented to the world press in March 1969, two months after the El Primero. However, because caliber 11 was simpler in design than the El Primero, beating at only 19,800 vph, watches containing it beat Zenith to market appearing in August.

Unknown to the Swiss, Seiko had also been working on two automatic chronograph movements since 1968. The first was the integrated, vertical clutch 6138 movement that had minute and hour totalizers, manual winding and day and date quickset. Technically, it was a formidable beast but alas, it proved a challenge to manufacture not appearing until late 1969/early 1970. However, the simpler 6139 that lacked the 6138’s hour totalizer and manual winding proved less challenging to manufacture and has been found in watches manufactured in February 1969. Seiko eventually and quietly announced the 6139 to the world in May 1969, three months after they had started selling the watches in Japan.

So who was first? Well, in true 21st century style, everyone gets a participation medal: Zenith, for the first announcement and the sheer marketing chutzpah to literally call their movement ‘the first’, Seiko for being the first to build and selling an automatic chronograph, and the caliber 11 partners for being the first to sell automatic chronographs in Switzerland.