The rotonde de cartier annual calendar is a robust and practical addition to the brand’s collection

Thirty days hath September, April, June and November,” goeth the doggerel verse, reminding us of the irregularity of the Gregorian calendar — a verse which also serves to remind owners of mechanical watches with simple calendars that for five months out of the year (including February), they’ll have to manually correct the date their watches show. A calendar complication that never requires correction was a dream eventually realized in the perpetual-calendar watch, which not only automatically accounts for the varying lengths of all the months, but also knows when it’s a leap year and accordingly adds an extra day to the month of February.

The perpetual calendar is not without its downsides, though. It’s complicated (it’s considered one of the three complications traditionally necessary for a watch to be dubbed a “grande complication” timepiece), it’s delicate, and for much of its history, it’s been difficult to correct (and easy to damage while doing so). In order to avoid these pitfalls and retain the advantages, the annual-calendar complication was invented — and surprisingly recently; the first annual-calendar wristwatch was Patek Philippe’s ref. 5035, which was shown at BaselWorld in 1997. Since then, the relative simplicity, robustness and ease of use of the annual relative to the perpetual calendar has made it increasingly attractive to both watchmakers and watch owners, although it’s still a relatively rare complication.

Cartier’s first annual-calendar wristwatch was introduced at this year’s SIHH: the Rotonde de Cartier Annual Calendar, which stands in contrast to and complements Cartier’s first in-house minute repeater; a practical and robust brother to the timepiece that is Cartier’s demonstration of its mastery of what’s generally considered the most challenging complication in watchmaking. The Rotonde de Cartier Annual Calendar’s development began with the firm’s own in-house self-winding movement, the 1904 MC. It is not, however, a module. Instead, the annual-calendar mechanism has been built directly into the caliber 1904 MC, resulting in the integrated self-winding perpetual-calendar caliber 9908 MC. It’s a relatively high-frequency movement beating at 4Hz (28,800vph), and brings to the table a 48-hour power reserve.

One of the most distinguishing characteristics of the complicated watches in Cartier’s Fine Watchmaking collection is the presentation of information with exemplary clarity and creativity. For instance, one of our favorites, the central chronograph, uses a very clever combination of a multi-level dial and rotating disc for the minutes indication to present a chronograph watch in which every indication is always readable no matter the time or interval timed. The Rotonde de Cartier Annual Calendar is designed along the same priorities. The large date display, combined with a multi-level dial with indications for the day of the week and the month, make it one of the most easily read annual-calendar watches around.

The combination of ease of use and elegance is built into the movement design as well; to spare the owner the chore of fiddling with correctors, all of the calendar indications on the Rotonde de CarCartier Rotonde De Cartier

Annual Calendartier Annual Calendar can be controlled from the winding crown.