An interview with Tonda PF Chronograph Mysterieuse CEO Parmigiani Fleurier. He talks about the development secrets of the "Tonda PF Chronograph Mysterieuse," which "conceals the chronograph function."

At first glance, it looks like a simple three-hand watch. However, by pressing the push button at the 7:30 position, the functions of the various hands switch, transforming the Parmigiani Fleurier "Tonda PF Chronograph Mystérieuse" into a wristwatch that can simultaneously measure both the chronograph and the current time. We asked CEO Guido Terreni about the origins of this innovative idea.

What's important to us is that something is elegant while still having functionality behind the scenes.

　Parmigiani Fleurier's new "Tonda PF Chronograph Mystérieuse" incorporates the unconventional idea of ​​concealing the chronograph hands when not in use. "I came up with the idea for this watch in September 2021, the same day as the GMT (which allows the sub-hour hands to be hidden)," recalls CEO Guido Terreni.

"After creating the GMT function that only appears when needed, I thought about what to make next. The idea stemmed from the rotating bezel of a diver's watch that can record time. Nobody had thought of doing it before, but I thought it would be possible to perform the same function as a rotating bezel using a movement."

　When the chronograph is not in use, it's a three-hand model that displays the hours, minutes, and seconds. However, the moment the chronograph is activated, the white gold hour hand moves to the 60-minute counter, the minute hand to the 12-hour counter, and the second hand to the chronograph seconds hand, while the rose gold hand indicates the current time. Then, when the button is pressed again, the white gold chronograph hour and minute hands overlap the rose gold hour and minute hands that indicate the current time, transforming it back into a three-hand model. "Normally, the time display hands and the chronograph hands are not linked, but thanks to the mechanical memory, the hands remember their respective positions. Therefore, when reset, the hands are hidden by the hour and minute hands."

　However, given that it took four years to develop, its configuration is extremely complex. Because it needs to move three gears—seconds, minutes, and hours—it has one vertical clutch to move the chronograph seconds hand and two horizontal clutches to move the 60-minute and 12-hour totalizers.

　The size is also exquisite. Despite having a configuration where five hands overlap in the center, the case is 40mm in diameter and 13mm thick. And the movement is only 6.9mm thick. "Initially, we specified 12mm, but during development, we were asked if we could add another 1mm. Even so, it's about the same thickness as a regular chronograph." In addition, Terreni made fine adjustments to the hands.

"Since all the hands are in the center of the dial, the five hands overlap. Therefore, the dimensions of the hands are not exactly the same. When viewed from above, the hands that are hidden are slightly smaller. If they were the same size, they would be visible."

　Despite having so many intricate features, this new model is surprisingly understated in appearance, almost indistinguishable from existing GMT models. When I suggested that a chronograph with such an unprecedented mechanism might have benefited from a drastically different design and color scheme, Terreni emphasized, "That is precisely the identity of Parmigiani Fleurier."

"Having modesty is at the heart of the private luxury we advocate. It is luxury underpinned by refinement, not for social approval, but to express one's own culture, taste, and sophistication. So this model, too, is elegant, yet its functionality lies in the background." The Tonda PF Chronograph Mysterieuse completely conceals its chronograph function. Perhaps this ultimate level of refinement is the company's "consistency."