For URWERK, the foundation of a precision timepiece should be a precise, reliable and durable movement. Such a movement should meet specific criteria, including accuracy in 5 positions between -4 seconds and +6 seconds over a 24-hour period. However, while it is one thing to regulate a precise watch in the controlled world of a studio, its performance can be very different in the sometimes extreme real world (i.e. on the wrist). Changes in position and temperature, as well as shocks, can adversely affect the isochronism (regularity of timekeepi