The true beauty of the Retrograde Annual Calendar lies in the fact that the wearer maintains a point of contact with the watch each year. The date is automatically adjusted based on the number of days in the month — 30 or 31 — but it works on the basis of 29 days for February, whether or not it is a leap year. Therefore, once a year, or rather, three times every four years, at the end of February, the wearer of the Tonda Annual Calendar can remove the watch from his or her wrist and re-establish contact with its subtle mechanism by setting the date manually. It can then be left alone to follow its path flawlessly for the next 365 days. The retrograde date indication never obscures the moon phases at 6 o'clock, showcasing this highly poetic complication. The day of the week and the month are shown in windows at 9 o'clock and 3 o'clock respectively, for perfect legibility. 
 

Compared to its predecessor, the Tonda Quator launched in 2011, the Tonda Annual Calendar is notable for its understated character and legibility. The designers have enlarged the bezel to reveal as much of the dial as possible. The minute track and indices sit on the outside, producing a floating effect and guaranteeing highly accurate time reading. The numerals on the retrograde date are arranged on the inside, harmoniously encompassing the day and month counters. The dial is constructed in several levels, and the three-dimensional arrangement of the various counters creates its relief and richness. The hands are slimmer and more elongated than previously, although their proportions are perfectly in line with the golden ratio beloved of Michel Parmigiani. The Tonda Annual Calendar is available in two versions: a rose gold case with a white grained dial – a speciality of the manufacture; a white gold case with a black opaline dial.