Building A Chronograph: The New RRCHF Flyback Chronograph From Rexhep Rexhepi

The first time I visited Cartier’s new manufacture in La-Chaux-de-Fonds, it was in 2008 and the company’s technical director was Carole Forestier-Kasapi. Forestier-Kasapi is now at TAG Heuer, but at the time, her work at Cartier was focused on the inventive complications that formed the Fine Watchmaking Collection, and which included exotica like the Rotonde de Cartier Astrotourbillon. I asked her at the time if tourbillons were in general, the most challenging mechanism to construct, and she replied, “No. Chronographs are hard.” The ubiquity of chronographs in modern watchmaking may tend to make us think otherwise, but the chronograph certainly post-dates the tourbillon (the Louis Moinet Compteur de Tierces, from 1816, is an incredible achievement but it is a stopwatch, not a chronograph as such) and there is a reason why chronographs in general rely on a certain basic set of calibers, layouts, and technical solutions.

Rexhep Rexhepi’s newest release is a chronograph: the RRCHF Flyback Chronograph. This is the first new watch from Rexhepi since his collaboration with Louis Vuitton – the LVRR-01 Chronograph à Sonnerie, in 2023 – and Rexhepi’s reputation as well as the unfailingly high standards of his work, make the new release a major event. The design of the chronograph, and the layout of the movement, follow on the symmetrical movement layout of the Chronomètre Contémporaine, and is a further development in some features of the Chronomètre Antimagnetique, auctioned in 2024 at Christie’s for Only Watch. The movement architecture is both very classical in its general spirit and in the execution of the fine details, but it’s also immediately recognizable as a Rexhep Rexhepi movement, and in a domain of watchmaking as inherently conservative as chronograph construction, this is an achievement which required some subtle but significant departures from business as usual.

The Layout Of A Classic Chronograph

A chronograph is essentially a watch in which a standard timekeeping train drives a separate elapsed time train, and this means you need a mechanical clutch which can connect and disconnect the two, at the user’s discretion.

The elapsed time gear train must not only record elapsed time, but must also contain components which start, stop, and reset the elapsed time hands, or recorders. One of the key challenges in constructing a chronograph, is that the entire elapsed time train is driven off the last gear in the going train – the fourth wheel, which turns once per minute. This is the furthest gear from the mainspring barrel except for the escape wheel itself, which means the available torque is quite low; and so the elapsed time mechanism has to be constructed so that the energy needed to run it is kept to a minimum. Switching on a chronograph will cause a drop in balance amplitude but the trick is to minimize this as much as possible.

The position of the fourth wheel, since it turns once per second, determines the location of the running seconds hand. In a chronograph, there is a driving wheel on the same axis as the fourth wheel, which drives an intermediate wheel. When the chronograph is switched on, the intermediate wheel drops into place between the driving wheel, and the chronograph seconds wheel, which begins to turn. The chronograph seconds hand is on the axis of the seconds wheel and begins to turn along with it, recording elapsed seconds. An example of this construction is the variation on the Lemania 2310 found in the Patek Philippe chronograph 5070.

The base caliber is from Lemania, in this instance, but significantly reworked both technically and aesthetically. In the shot of the movement, you can see the cock for the escape wheel just to the left of the balance, and working backwards along the going train, you can see the chronograph driving wheel on the fourth wheel pivot, with the actual fourth wheel underneath it, and the running seconds subdial on the dial side. The entire chronograph mechanism, including all the levers, the column wheel, and the brake and reset to zero hammers, all sit on a plate that covers the going train, except for the escape wheel and balance.

The fourth wheel location determines the location of the running seconds hand and therefore, the layout of the dial overall.

The Movement Design Of The RRCHF Flyback Chronograph

Looking at Rexhepi’s preceding work, we can trace the evolution of the placement of elements of the going and elapsed time gear trains. The basic identifying feature of Rexhepi’s movement layout is the commitment to symmetry, with the mainspring barrel under a bridge exactly at the 12:00 position. (The exception to this is the Chronomètre Contemporaine II, which has two mainspring barrels, although the use of symmetry is the same). In the Chronomètre Contemporaine, the single mainspring barrel powers the center, third, and fourth wheels, with the center wheel under its own bridge, and symmetrically arranged separate cocks, going anticlockwise, for the third and fourth wheels, and for the balance.

The Antimagnetique has a notably different movement architecture, which is thanks to the use of a center seconds display, rather than a small seconds display.

Notice the altered position of the fourth wheel, compared to the Chronomètre Contemporaine. The mainspring is still in the same position, but the balance is now at 6:00, directly opposite the mainspring barrel, with the fourth wheel under its cock to the upper right of the balance. The fourth wheel now has an extra wheel above it, on the same axis, which drives an intermediate wheel geared to the central running seconds hand. The watch therefore has an indirect center seconds (most modern watches with center seconds hands, are designed so that the movement fourth wheel is in the center of the movement, driving the center seconds hand directly). The indirect center seconds wheel sits under its own elegantly curved bridge, which symmetrically spans the diameter of the movement exactly on its horizontal axis. The watch has a reset to zero function: the seconds hand resets to the 12:00 position when the crown is pulled out to set the time. This is thanks to a heart cam and hammer system, with the reset to zero hammer pivoting on a jewel in a cock on the lower left, where it is visually symmetrical with the fourth wheel cock. It’s a beautiful and ingenious layout which anticipates the RRCHF Flyback Chronograph.

One of the first things we notice about the RRCHF, compared to classic chronographs, is that its layout is a bit unusual. Typically, a classic chronograph like the Patek 5070 has the running seconds subdial and the minutes subdial on the horizontal axis of the watch, in line with the crown; there are however revered exceptions to this rule, including the Lange Datograph and the 1815 Chronograph; in the former case, this is in the interests of clearing space for the big date display at 12:00. Here there’s a similar rationale – the hour and minute hands are in their own subdial at 12:00, and to clear space for them, the chronograph minute recorder, and the small seconds subdial, are completely below the horizontal midline.

Of course this is a little bit of a chicken and egg question – if the RRCHF is derived from, or a development of, the Antimagnetique, then the placement of the dials may have been necessitated by the layout of the Antimagnetique’s movement; or, conversely, the RRCHF may have been already conceptualized, with the Antimagnetique a sort of early prototype as well as a very interesting watch in its own right. The whole question may be a bit of a McGuffin, of course – creative processes, especially at this scale and at this level of quality, are seldom simply linear and generally not driven primarily by pragmatic considerations.

The RRCHF is described as an “integrated chronograph” by Rexhepi, but I think it’s worth pointing out that that means something specific in this case. In most classic hand wound chronographs, the mainspring is not visible, as it and the going train are under an upper plate which holds the pivots for the elapsed time train. In the RRCHF, there is no upper plate for the chronograph train. This allows the movement, for all its visual depth, to be relatively thin, at 6.3mm and the RRCHF is in fact a bit thinner than the Antimagnetique: 9.7mm overall, vs. 9.9mm for the Antimagnetique.

The RRCHF does not have the reset to zero time setting capability of the Automatique but that’s thanks to the use of the space for the chronograph flyback and reset to zero systems. In the Automatique, the reset lever pivoted on a cock in the same location where we now have the minute recorder, and to have reset to zero hand setting would require a heart piece on the fourth wheel, with an additional lever.

In the RRCHF, we can see the chronograph center seconds wheel in the middle of the movement, under its own bridge (like that of the center seconds wheel in the Antimagnètique, the bridge spans the diameter of the movement across the horizontal midline) with the fourth wheel and its co-axial chronograph driving wheel on the lower right. At the lower left, we can see the saw-toothed wheel for the instantaneous jumping minutes; as each minute elapses, the pawl next to it draws the wheel around one increment (the pawl is tripped by a snail cam on the seconds wheel). If you’re wondering where the column wheel is, you can see it, if you look very closely, hiding under the upper edge of the sawtoothed minute wheel:

I think we can reasonably expect the quality of workmanship to be as exceptional as usual. The overall effect is really impressive and as I said above, you know instantly whose work you’re looking at. The combination of powerful visual symmetry with very subtle asymmetries could only have come about with a combination of excellence in design, with a very deep technical knowledge of watchmaking and integrating those in turn with a well developed, apparently mature movement decoration vocabulary puts the RRCHF in a class apart from virtually all other high grade chronographs.

I’ve been dwelling quite a lot on the sort of intersection of mechanics and design that the movement represents, and what the movement design looks like in the larger context of traditional classic hand wound chronograph design, and Rexhepi’s previous work, but of course, the whole watch shows the same level of attention to detail. On the dial side, we have things like the very elegant, elongated chronograph center seconds hand, which spans almost the entire diameter of the dial and which reinforces the sense of dynamic symmetry of the watch overall; the subtle differentiations of color in the chronograph hands versus those for telling the time, and the design of the minutes track, which (and it’s hard to unsee once you see it) gives the impression that the watch is smiling cheerfully at you.

The point about the degree to which the chronograph is challenging as a complication, is perhaps borne out by the relative lack of chronographs from most independents; those who do have chronographs in their portfolios and want to do something a bit off the beaten path, usually use outsourced calibers like the Agengraphe. Actual new chronograph movements – net new ones – are extremely rare and the fact that Rexhepi has actually designed and built one, says at least as much about his horological bona fides as the quality of his movement finishing (not that his bona fides were really in doubt anyway). As Carole Forestier-Kasapi said to me many years ago, chronographs are indeed hard, and when a new one is made, sometimes one is less amazed to see it done well than surprised to see it done at all. The RRCHF Flyback looks very much as if it is, in fact, not just done, but done very well indeed.

The RRCHF Chronograph Flyback: case, platinum or rose gold, with grand feu blue or black dials; 38.8mm x 9.7mm; water reistance, 30M. Movement, flyback chronograph with seconds and instantaneous minutes; lateral clutch with column wheel, running at 21,600 vph with a 72 hour power reserve. Price, CHF 150,000; limited production but not a limited edition. For more info, visit RexhepRexhepi.com.