Jaeger-LeCoultre pulled out all the stops at SIHH 2019 this year when it unveiled the Master Grande Tradition Gyrotourbillon Westminster Perpétuel, the latest generation of multi-axis tourbillon to emerge from the Le-Sentier maison. This timepiece combines a perpetual calendar, a minute repeater with Westminister chime and a constant force mechanism to ensure a steady supply of power to the escapement. 

A sketch of this mega timepiece

It may be recalled the Jaeger-LeCoultre first introduced its mutli-axis Gyrotourbillon in the 2004 Master Gyrotourbillon 1, followed by the 2008 Reverso Gyrotourbillon 2, the 2013 Master Grande Tradition Gyrotourbillon 3 Jubilee and the 2016 Reverso Tribute Gyrotourbillon.

This watch features a gyrotourbillon that is significantly smaller than those in the preceding Gyrotourbillon timepieces. Reducing the size of a mechanism also reduces its error tolerance, which is why successful miniaturization efforts are so highly valued and complex.

The Gyrotourbillon dominates the openworked dial

It uses a 43 mm white gold case that is 14.08 mm thick and features a mix of polished surfaces, sandblasted flanks and a highly polished narrow bezel. The deep blue grand feuenamel dial, common to the new Master limited edition series launched at SIHH 2019, is bordered by a grained silver ring that houses the engraved date ring. The perpetual calendar’s indications – day, month and date - are placed in harmony across this enamel dial. 

The date can be adjusted forwards or backwards and pointer-style date indication jumps over the tourbillon aperture in order to provide the best possible view of the visually stunning rotating escapement. The dial is also available in a more classic silver-grained version.

The four gongs of the chiming mechanism are visible on the dial

However, the openworked dial is dominated by the multi-axis Gyrotourbillon which is placed in a voluminous cavity at 6 o’ clock. The minute repeater uses four blue crystal gongs and four trebuchet hammers that are clearly visible on the dial. The Westminster chime’s four-phrase melody is composed of four notes played in different sequences and different quantities at each quarter of the hour.

In order to ensure a quality chime, this watch has a silence-reduction function built into its chiming mechanism. This ensures that even when the full set of Westminster quarters is not struck, there is no time delay corresponding to the missing quarters before the minutes are struck. In every instance of the chime when the Master Grande Tradition Gyrotourbillon Westminster Perpétuel is activated, the hour strikes, quarter strikes and minute strikes are seamlessly joined.

The gorgeous caseback features excellent finishing

A one-minute constant-force mechanism provides a consistent level of power for the energy-hungry tourbillon without affecting its chronometric ability. A spring, known classically as a remontoir d’égalitéis periodically wound by the mainspring and acts as a secondary power source to protect the regulating organ of the movement. The constant-force mechanism regulates the motion of the minute wheel, creating a jumping minutes hand that offers greater precision in time display. 

More significantly, the mechanism that controls the minute strike also follows this one-minute jumping system, which completely eliminates the chiming error that can occur when the repeater is activated between minutes, when the chime played and the time shown can be one minute apart.

This timepiece is limited to just 18 pieces. The watch is expected to be priced at around €955,000.