For chronograph fans, there are all sorts of interesting little sub-niches under the larger umbrella of stopwatch inspired timekeepers. There are flyback chronos, which enable the user to rapidly reset elapsed time, helpful if timing multiple heats of a race. Similarly, split-second chronographs allow for an additional timing behind the initial seconds tracking, which is incredibly useful if keeping track of, let?s say, multiple laps in a race. And of course you have chronos in all different types of styles, from dressy to casual, with scales designed to measure to everything from average speed, to a human pulse.
Monopusher chronographs, which we?ll be looking at today, occupy their own strange corner of Chrono world. Unlike a two button chronograph where starting, stopping, and resetting requires interacting with multiple pushers, a monopusher, naturally, only has one. The mechanical benefit here is clear: whereas on a traditional 2 button system the chronograph works could potentially be damaged by resetting before stopping, the more robust monopusher design eliminates this as a possibility. It?s simply impossible to actuate the chronograph commands out of order. 
The business end of the Patek Philippe 5372P.

With only one pusher, a monopusher chronograph is also going to have a distinctly different look than a similar watch with a two button layout. The lack of symmetry or feeling of busyness that many dislike about chronographs is less of a concern with some...