The Audemars Piguet Heritage Department recently published: Making the Leap – the first article in a series that delves into the world of the companies historic full calendar and perpetual calendar wristwatches of the 20th century. They have now published their second article in the series, Function, Form & Phases of the Moon. The article sheds light on the influential role played by Audemars Piguet calibre 9/10RSQ towards the evolution of the calendar wristwatch and towards broader horological design of the late 1940s – 1960s.
The AP Calibre 9/10RSQ was a rare caliber, with only 68 examples produced. It was based off of the Calibre 9/10RS of which about 2,800 were produced but most of which were time only and thus not quite as special as the 9/10RSQ. The calendar full caliber full calendar calibers found their way into four distinct Audemars Piguet models: references 5504, 5513, 5514 & 5515. These references comprise both square and round cased watches.