While there are many staple complications such as the chronograph, calendar, alarm watch and so on, one that is lesser known is the mono-rattrapante. Made famous by Bovet in the 40’s, these watches were unique in their complication and while it looks like your standard chronograph on the surface, there is much more functionality to it.
To begin with basics, a rattrapante, also known as a split seconds chronograph, is a highly complicated calibre that is intended to allow the user to time multiple events with two different running chronograph hands. The mono-rattrapante on the other hand, as the name implies, is a much simpler take on this, using only one chronograph hand and achieving most the functionality.
How it works is that pressing the top button starts stops and resets the chronograph, just like how a mono-pusher chronograph would work. While the chronograph is activated and running, the user can press and hold down the bottom pusher and the chronograph hand will stop, allowing the ability to record the current time. When the bottom pusher is let go, the chronograph hand will jump to where it should’ve been all along if it were continuously running. This as you can see, acts as a split-seconds chronograph, allowing for the recording of multiple times in one session.
Furthermore, what is very more special about this example is that you will notice that the top pusher has an unusual notch. As the top pusher only allows the chronograph to start, stop and reset, it is limited in its functionality and does not allow the user to continue the timing once it has been stopped. This ingenious notch allows the user to use his nail and lift up the pusher, which then reactivates the chronograph, instead of resetting.
You can tell that this is a very thoroughly complicated watch with a lot of functionality. Perhaps it is not as popular as it is quite hard to explain. While Bovet was famous and made most of these Valjoux 84 powered watches, Recta made a few examples, making this one even rarer than its Bovet counterparts.