The A. Lange & Söhne Grand Complication is a watch that generated excitement and controversy almost immediately, and not without reason.  First, there was the manner of its introduction –it was the company’s star debut at the 2013 SIHH, and yet almost no one was able to actually see it.  Then there was the size –50mm, and 20.3mm thick.  Matching its gargantuan dimensions was an equally staggering price –in US dollars, over $2.5 million.  And, of course, there was its enormous complexity –876 components, running in 67 jewels, the calibre L1902 is one of the most complicated watch movements in existence:

Grand and Petite Sonnerie, Minute Repeater, Perpetual Calendar showing the Age and Phase of the Moon, Indication of the Leap Year, Split-Seconds Monopusher Chronograph with 1/5 Second foudroyante (“lightning seconds”) hand, with 18k gold escape wheel and Glashütte-type lever.

The term “grand complication” has become somewhat elastic in use in recent years, but classically it meant something very specific: a perpetual calendar, with a chiming complication (at least a minute repeater) and a rattrapante chronograph.  By this definition grand complication watches are very rare.  The A. Lange & Söhne Grand Complication wristwatch was some seven years in the making and was in many respects directly inspired by no. 42500, which was made in 1902 and whose restoration occupied around 5000 working hours.  The pocket watch no. 42500 is commemorated in the name of the Grand Complication wristwatch’s movement, which is designated cal. L1902.  The wristwatch –ref. 912.032 –is essentially a smaller version of the 42500 Grand Complication pocket watch.  The latter is a very large, heavy clock-watch, with the movement alone some 45 mm in diameter and over two centimeters thick, and the wristwatch ref. 912.032 has reduced the size of the movement to 40mm and the height to 14.2 mm.

Reduction in size notwithstanding ref. 912.032 is a massive watch; its proportions are those of a statement piece (to put it mildly.)  The case is 50 mm in diameter and 20.3 mm thick, in heavy pink gold, and it has in the hand a feel of solidity and permanence well in keeping with its role as a benchmark for complexity and sophistication for A. Lange & Söhne.  Comments on wearability seem almost silly in this context, or at least beside the point, and yet, we were told by A. Lange & Söhne technical director Anthony de Haas, who oversaw the seven year process of developing the wristwatch, that a great deal of effort was expended on ensuring that the watch could in fact be worn daily with the expectation that it would (unlike many other very complicated wristwatches) function properly under normal conditions of wear.

The wristwatch Grand Complication is in a sense a physical museum of the history of watchmaking, at least as approached from a certain perspective and with a certain philosophy, and as such there are many stories that could be told using it as a point of departure.  For example, great care was taken during its construction to ensure that the amplitude of the balance would not suffer during use, under any circumstances.  The most challenging time for the watch in this respect is just before midnight at the end of the month, when the perpetual calendar indications all switch; if at the same time the owner activates the chronograph, and then the split-time function this puts the maximum amount of additional drain on the energy from the mainspring (the chiming functions don’t affect balance amplitude as they have their own dedicated mainspring barrel.)  The watch has been so carefully adjusted, however, that even under these trying conditions, the balance amplitude drops by no more than 30 degrees –well within the limits necessary to maintain good timekeeping.

Calibre L2902.  Please note this is a (fully functional) prototype and that movement finish is not yet finalized.

Another intriguing feature is the use of a gold escape wheel and lever –the escapement, in fact, is in the wristwatch the same as in the pocket watch; it is a type known as a Glashütte lever, which has several interesting features.  The use of a hardened 18k gold alloy for these essential parts means they are antimagnetic.  In the lever, the pallet jewels are not held in place by shellac, as in the Swiss lever –they are instead set directly into the metal of the lever and their impulse surfaces are slightly rounded, which was thought to reduce the degree of adhesion produced by the oil used on the impulse surfaces.

The dial is grand feu enamel, in five separate components: the main dial, and four sub-dials.  The aperture in the main dial is cut with a fine saw (a laser can’t be used as it would burn the enamel) and the risk of breakage is very high, but it’s the only way to do it.

Perhaps one of the most interesting aspects of the Grand Complication wristwatch, however, is the use of a foudroyante or “lightning” seconds complication for the chronograph.  The foudroyante is basically an additional hand that allows fractions of a second to be timed as well; it consists of a sub-dial in which a hand rotates once per second, pausing for an instant at intervals equal to the number of oscillations per second of the balance.  An 18,000 vph balance like the one used in the Grand Complication wristwatch yields a 1/5 second foudroyante hand (sometimes also called a diablotine (“little devil”) or flying seconds hand.

Flying seconds complication. Below, 30 toothed wheel on axis of escape wheel; above, two level wheel on pinion of flying seconds hand.  Note the longest tooth at 12:00 for re-set to zero.

Here’s how it works: the pinion of the escape wheel has mounted on it a wheel with 30 teeth, which advances  every time the escape wheel unlocks and advances.  The lightning seconds hand is fixed to a pinion which is also the axis of a two-level star wheel.  Viewed from the back of the movement, the upper star wheel has five teeth –one longer than the rest –and the lower has five teeth as well; the two wheels are connected by a pin in the upper wheel that runs through a groove cut in the lower.  The lightning seconds hand is driven by its own, dedicated mainspring.  When the chronograph is activated, the lower five-toothed star wheel starts to turn under the power of the lightning seconds mainspring, but is blocked by one of the teeth on the 30 tooth wheel (which, you’ll recall, is on the same pivot as the escape wheel.)  As the escape wheel unlocks and advances, the 30 tooth wheel advances as well and the lower star wheel is allowed to advance one increment, until the next tooth is blocked.  This happens five times per second as long as the chronograph is running.

The upper wheel is there to hold the lightning seconds hand in position during stopping and re-set of the chronograph.  When the chronograph button is pushed to stop the chronograph, a stop lever drops into position and blocks one of the teeth of the upper star wheel.  The upper star wheel is held in position by pressure against the stop lever beak, by the force of the lightning seconds spring, until the chronograph is started again.  The pin-and-groove connection between the upper and lower star wheels allows the lower star wheel to have its teeth pushed clear of the 30 tooth wheel on the escape wheel pinion –otherwise stopping the chronograph would stop the entire watch.

When the chronograph is re-set to zero, the stop lever draws back slightly so the teeth of the upper star wheel can clear it and the lightning seconds hand is free to rotate. However, the stop lever only draws back far enough to allow four of the five upper star wheel teeth to pass –the fifth, which is slightly longer, is blocked by the stop lever and the lightning seconds hand stops turning, at exactly the zero position.

Hand-engraved balance cock; overcoil balance spring. The configuration of the balance cock, regulator, and stud are taken directly from the pocket watch ref. 42500.

It’s a simple, ingenious mechanism –which, however, has been significantly updated for the wristwatch.  The mechanism in the pocket watch works but the materials of the day would be worn out in half an hour if the chronograph were allowed to run.  Mr. de Haas shared with us that the wristwatch, on the other hand, is the beneficiary of materials upgrades that allow the lightning seconds hand to be run with impunity –though in a manner characteristic of watchmakers protecting trade secrets throughout the centuries, he became charmingly vague when pressed for details.

The wristwatch, therefore, is indeed profoundly faithful to the design and spirit of the original pocket watch but with a host of refinements and improvements.  Six will be made at the rather staggering cost of EUR 1.92 million, and one will be created per year.  The watch shown in this article is No. 0, the prototype, which will remain in the hands of A. Lange & Söhne.

Jack Forster is the Editor in Chief of Revolution Magazine USA.  Follow revolutionmag on Instagram and Revo_Online on Twitter; Revolution International Digital Edition is available to download via the Zinio app for iOS, Android, and desktop.