Whats a Reserve de Marche?
A Reserve de Marche, or Power Reserve, is an indicator that displays the approximate number of days or hours left on the current state of mainspring wind. This typically cannot be done by a simple gear train, since a watch is wound from the center arbor of the barrel, and the power is removed from the outer rim of the barrel. Therefore, a gear train that can act as a differential is required to read out the difference between the arbor position and the barrel rim position. This can be a very useful complication, as it lets one know whether a watch is wound before putting it on. This is true for automatics (which may be in any state of wind) or long power reserve watches (such as the Eberhard 8 days, Lange 1, or the new Patek 5100 ten-day reserve).
A Reserve de Marche, or Power Reserve, is an indicator that displays the approximate number of days or hours left on the current state of mainspring wind. This typically cannot be done by a simple gear train, since a watch is wound from the center arbor of the barrel, and the power is removed from the outer rim of the barrel. Therefore, a gear train that can act as a differential is required to read out the difference between the arbor position and the barrel rim position. This can be a very useful complication, as it lets one know whether a watch is wound before putting it on. This is true for automatics (which may be in any state of wind) or long power reserve watches (such as the Eberhard 8 days, Lange 1, or the Patek 5100 ten-day reserve).
