Taking the ‘Leap’
The perpetual calendar is the most complex calendar for it includes the day, date and month but also takes leap years into account (apart from in 2100, that is, when the leap year will be skipped.) Hiren Kumar Bose on the perpetual calendars showcased at the SIHH 2016
Unlike simple calendars requiring manual correction after every month with less than 31 days, the perpetual calendar takes account of the leap-year cycle with its 31-, 30- and 28-day months, as well as the quadrennial recurrence of February 29th. It requires significant miniaturisation in order to achieve an ultra-thin perpetual calendar that mechanically adjusts to keep track of calendar irregularities.
H.MOSER & CIE. Endeavour Perpetual Calendar Concept Funky Blue
Two hands, one arrow-shaped centre hand, a big date display and a star. These are the only embellishments found on this watch, presumably the most minimalist perpetual calendar ever produced. By focusing on the essential, H. Moser & Cie. invites you to rediscover its perpetual calendar in a Concept version that features neither indices nor logo, stripped of its small seconds dial and power reserve indicator, in an exceptional material for the Manufacture: steel.
Bridging the past and present, the 40.8mm watch recalls the beginnings of watchmaking, to a time when only the movement would bear a maker’s mark. For the new version of its flagship model, H. Moser & Cie. has gone one step further: in addition to the indices, logo and small seconds dial, the power reserve indicator has also been removed. The only elements remaining on the famous sky-blue fumé dial are the date display at three o’clock, the leaf-shaped hour and minute hands and an arrow-shaped centre hand. This final hand is an ingenious marvel that indicates the months. The hand-wound HMC 341 calibre has a minimum power reserve of 7 days and a mechanism to adjust the date forwards or backwards at any time of day and the leap year cycle indicator on movement side. During this leap year, relive the rare experience of the date change from February 29th to March 1st again and again.
AUDEMARS PIGUET Royal Oak Perpetual Calendar
When the iconic Royal Oak came out in 1972, Audemars Piguet caused a sensation by encasing the piece in an everyday material, stainless steel. Now, nearly 45 years later, the watchmaker embraces its luxury roots with a complicated variation housed in a 41 mm yellow-gold case, the Royal Oak Perpetual Calendar. The subtly textured blue dial features a leap-year indication at 12 o’clock, an astronomical moon phase at 6 o’clock, and the week of the year on the outer chapter ring.
A.LANGE & SOHNE Lange 1 Tourbillon Perpetual Calendar
The watch combines two classic complications with the iconic design of A. Lange & Söhne’s most famous watch family. The calendar consists of a Lange outsize date, retrograde day-of-the-week and leap-year displays and a peripheral month ring. Due to the clear separation of the time and date, all information can be taken in at even a cursory glance. All of the perpetual calendar displays advance instantaneously. The mechanism is designed in such a way that it must be advanced only by one day in the year 2100. And the moon-phase display, located inside the subsidiary seconds dial, will even run true for 122.6 years before it needs to be corrected by one day. A subtle inscription beneath the twelve refers to the existence of the tourbillon. By looking through the sapphire-crystal caseback, it can be admired in all its technical complexity. The movement is equipped with Lange’s patented stop-seconds mechanism. It brings the balance inside the tourbillon cage to a standstill instantly, gently and safely when the crown is pulled. This allows the watch to be set with one-second accuracy. A solid central rotor with a 21-ct-gold segment in the middle and an additional platinum centrifugal mass on the periphery efficiently tension the mainspring of the self-winding calibre L082.1 movement so that the maximum power reserve of 50 hours is built up after just a short time on the wrist. Typical Lange quality hallmarks include the lavishly decorated movement with hand-engraved tourbillon and intermediate wheel cocks as well as screwed gold chatons.
VACHERON CONSTANTIN’S Patrimony Perpetual Calendar Excellence Platine
Powered by the legendary Calibre 1120 QP, the watch has an ultra-thin mechanical self-winding movement developed and crafted in-house. It drives the hours and minutes hands, the moon phases at 6 o’clock along with a perpetual calendar displaying the day of the week in a counter at 9 o’clock, the date in a counter at 3 o’clock, the month and leap year in 48-month counters at 12 o’clock. It’s designed to stay accurate without any corrections until March 1, 2100. The Caliber 1120 QP measures just 4.05 mm thick, beats at the frequency of 2.75 Hz (19,800 vibrations per hour), and has a 40-hour power reserve. The watch is crafted in 950 platinum case, as is the dial. The slightly convex external zone is adorned with a circular “pearl” minute-track and 18-ct white gold applied hour-markers. The hours and minutes hands are in 18-ct white gold, while the calendar pointers are in blued steel. Revolving beneath the dial, the moon disc depicts the vault in white gold enhanced by a blue galvanic treatment. Each star has been crafted so as to provide an exact map of the sky. The sapphire case back affords a view of Caliber 1120 QP. This model is available in a limited and numbered 100-piece edition.
JAEGER-LECOULTRE Master Ultra Thin Perpetual
Jaeger-LeCoultre introduced a black dial version for their perpetual calendar, initially introduced in 2013. With only 9 mm thickness for 39 mm diameter, the case of the watch houses a perfectly balanced dial which showcases the different functions of the quantième perpétuel in a very clear manner: day, month, year and moon phases. The watch features polished rhodium-plated hour markers and small dots for minute markers. The perpetual calendar module is turned 180 degrees, with the moon phase now at 12 o’clock and the month sub-dial moved from 12 o’clock on the old, to the 6 o’clock position on the new. The year indication is at the side of the month sub-dial, between 7 and 8 o’clock. The dial of the watch displays the perpetual calendar indications in a balanced and extremely clear manner: day, month, date, year and moon phase. Once set, the automatic watch will not need any adjustment until 2100. The perpetual calendar mechanism takes into account the length of each month and counts 29th February every leap year.
