That is a Jaeger-Lecoultre Reverso.
Back in the days of colonial rule in India, a British Army officer is said to have dismounted from his polo pony in a distressed state after discovering his wristwatch had been smashed during a particularly hard-fought chukka.
Striding into the clubhouse, so the story goes, he related his misfortune to an entrepreneurial watch distributor called Cesar de Trey who took the tale of horological woe all the way back to the small mountain town of Le Sentier in Switzerland, where Jacques-David LeCoultre ran a watchmaking business established by his grandfather in the 1830s.
Rather than simply sending advice back to India that perhaps polo players ought to ride with their wrists unadorned, LeCoultre and his business partner Edmond Jaeger rose to the challenge of creating what could fairly be described as the first wristwatch specifically designed for a sport other than swimming.
With the help of a Parisian engineer called Rene-Alfred Chauvot – whose speciality was making dental instruments – they developed a rectangular watchcase that could be swivelled 180 degrees so its glass and dial were protected.
LeCoultre patented the idea in 1931 and called it the Reverso, explaining in contemporary advertising material that: “A watch, and more particularly a bracelet watch, is exposed to accidents in all spheres of social activities and sport. To be able to prevent these by a simple gesture is a very great advantage.”