The Excalibur Bi-Retrograde Calendar by Roger Dubuis

This year, Roger Dubuis celebrates its 30th anniversary, and for the occasion, the company pays tribute to its co-founder’s favourite complication: the bi-retrograde display.

This function, previously featured in the Excalibur Grande Complication alongside a dozen other highly complex mechanisms, takes centre stage once again. The Maison has also introduced a less complicated, more classic edition to further honour the bi-retrograde display.

Also referred to as “the ecliptic counters” by the Maison a nod to their elliptical shape and distinctive role in indicating the months and date the design showcases a symmetrical dial layout. Enhanced by refined detailing, it pays homage to the Maison’s early creations from 1996.

Glossary

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Glossary
fusee and chain

fusee and chain

Mechanism is an old mechanism used in mechanical watches to solve the issue of uneven distribution of power from the mainspring as it transitions from fully wound to relaxed state. The fusee consists of a cone-shaped device connected to the mainspring barrel by a chain.

The purpose of the fusee and chain mechanism is to maintain consistent torque during the movement of the mainspring and ensure equal power distribution. The cone-shaped fusee allows the chain to wrap around it in a way that compensates for the decreasing torque of the mainspring as it relaxes. This results in equal power distribution to the gears of the watch, leading to improved timing accuracy.

Simply put, when the chain is tightened with the necessary force, it supplies the gears with sufficient rotational power to maintain timing accuracy. When the mainspring is in a relaxed state, the effect directed to the gears decreases, allowing the chain to compensate and distribute power evenly to the gears, ensuring the continuity of timing accuracy.