Chopard L.U.C Perpetual Twin

The L.U.C Perpetual Twin by Chopard is a chronometer-certified perpetual calendar in steel. It has a logical and legible dial layout. The Twin in the name refers to the twin barrels connected in series providing a 58-hour power reserve.

The stainless steel case is 43 mm in diameter, 11.47 mm thick, with the standard 3 bar/30 metres water resistance. It has sleek, understated looks, provided by the smooth bezel, short lugs, and the coordination of detailing, such as the fluting on the crown that matches that of the caseband where it meets the bezel and caseback. The distinctive Roman numerals, the different metal finishes such as sunburst, high polish and brushed, give the watch an ever-changing personality according to its position in the light. The watch has a hand-sewn black alligator strap with a steel pin buckle.

The dial is great, with three subdials laid out like a tricompax chronograph. It includes a very logical arrangement of the leap year indicator. The calendar indications are grouped together, on the two central subdials that have darker grey rings bearing the indications. On the left, days of the week, on the right, months, and, in the February position, a small ring on which a tiny hand shows the leap year cycle. This is a brilliant intuition on the part of the Chopard designers, and involved some technical wizardry because the months ring has more space dedicated to February than the other months. The date is comfortably legible, with large numerals showing in two adjacent windows. The minutes scale at the edge of the dial is clear and complete, and likewise the small seconds scale on the subdial at 6 o’clock. The hour and minute hands are long and elegant.

Automatic L.U.C 96.51-L movement

The L.U.C 96.51-L is a perfect fit for the case, 33 mm in diameter, though the external ring on the steel caseback is quite wide. The movement’s balance runs at 28,800 vibrations per hour (4 Hertz), and the two barrels provide 58 hours power reserve. The watch is wound automatically by the micro-rotor that can be seen through the sapphire caseback. It is chronometer-certified by COSC, and nicely finished with circular-graining and Côtes de Genève.

The movement is based on the Chopard 1.96, with the addition of the perpetual calendar equipment on the dial side. It takes into account the differing duration of the months, and the leap year cycle. Somewhere at the heart of this movement, a wheel or a cam rotates once every four years. Recessed pushers on the caseband are used to adjust the calendar indications.