|This watch takes care of the “400-year-rule” to show the right time even in 2100.|
It would be easier for us to understand the seemingly simple yet extremely complex watch function if we know how the English (Gregorian) calendar came into being, replacing the erstwhile Julian Calendar. That the Julian Calendar was flawed and needed a reform had long been clear. The difference between the position of the sun and the calendar date had accumulated to nearly ten days in the 16th century. Pope Gregor XIII resolved to reform the faulty calendar and assigned the famous mathematician and astronomer Christopher Clavius the task of setting it right. On February 24, 1582, he published what we call today the “Gregorian calendar reform”. In the reformed calendar, he simply omitted ten days for an immediate correction of the existing difference between the sun and the calendar. Thursday, October 4, 1582, was immediately followed by Friday, October 15, 1582. Another reform that Clavius incorporated was not to reckon secular years (full centuries i.e. 1700, 1800, 1900 etc) as leap years unless their number is divisible by 400 without a remainder. This came to be known as ‘400-year-rule’
This new calendar with its rather simple rules is extremely precise: No further correction will be necessary for the next three thousand years. Then, the difference will again have accumulated to one full day.
We recently experienced the application of the 400-year-rule in the year 2000.
It is quite likely that this business of leap years- 1992 and 1996 being leap years, followed by another leap year four years later-does not strike us as very exciting or unique. Nevertheless, there was something remarkable about the fact that the year 2000 was a leap year, as it was the second time since the introduction of the Gregorian calendar (in 1582) that the 400-year-rule was applied. Both these secular years-1600 & 2000 (full centuries) are divisible by 400 without a remainder. Hence the century years 1700, 1800 and 1900 were not leap-years but 2000 was ! It may not sound very earthshaking, but it is undoubtedly a rare occurrence, nonetheless! Incidentally, the next one will be in year 2400!!!
Application of the 400-year-rule in fine watch making is rather complicated. It may be clarified that in horology, “complication” does not mean that something is wrong with your watch – it is the name for all functions that go beyond the display of hours, minutes and seconds. The name becomes understandable once we appreciate the fact that all these additional functions, from a simple date indication to a “Grande Sonnerie,” require more or less complicated additions to the basic movement. The most common complications are calendar indications, striking mechanisms, and chronograph functions, whereas tourbillons, astronomical indications (sidereal time, equation of time, rise and set of sun and moon), and jaquemarts are some of the rare and expensive complications.
The calender indications in watchmaking are defined as
The Annual Calendar: it will work fine for one year. It knows the lengths of the months (if they have 30 or 31 days) and only requires a correction once a year; when February turns to March. The plain/annual calendar was introduced rather early. Even the so-called “full calendar” with day, date, month, and moon phase indication is still a “plain calendar” as it requires manual interaction and correction in all months that have less than 31 days.
The Perpetual Calendar: it will work fine for all of us for the rest of our lives (except for those few who will still be alive in the year 2100 …). It can be simply defined as “Device that changes the date at the end of each month including the 29th February in leap years.” What sounds so simple requires a lot of knowledge to construct and a lot of horological precision workmanship to make. (A perpetual calendar adds about 100 parts to a movement.)
The perpetual calendar has been known in pocket watches since about 1615, but it was only used in wristwatches by Patek Philippe more than three centuries later. The first perpetual calendar wristwatch ever was made by Patek in 1925; it was based on a 1898 12” lady’s pocket watch calibre. Patek Philippe began the serial production of perpetual calendar wristwatches in 1941. It remained a speciality of the “Masters of Complication” for a long time. Today, about 20 years after the renaissance of the mechanical wristwatch, all major manufacturers offer perpetual calendar watches.
The Secular Calendar is a complication that has hardly ever been built into a watch. It takes into account the “400-year-rule” which means that only these calendars will jump directly from February 28 to March 1 in the year 2100 – all perpetual calendars will follow their 4-year-mechanism, and they will display “February 29” even in the year 2100. The secular calendar is a rarity, not even Patek Philippe’s 1933 “Graves Supercomplication” had this feature.
A watch is called a “Grande Complication” when it has at least a minute repeater with “grande” and “petite sonnerie,” a chronograph and a perpetual calendar. A watch needs at least three more complications to qualify as “Extra Compliqué” – there are not many watches of this type, and their price puts them far beyond a normal mortal’s reach.
The most complicated watch ever made, known in watch enthusiasts’ circles as “The Ultimate Watch,” is Patek Philippe’s “Calibre 89.” Patek Philippe holds a patent from 1986 for a “A secular perpetual calendar movement with retrograde indication”. The incredibly precise operation of 1728 parts in this really ultimate masterpiece of watchmaking allows to perform no less than thirty-three complicated functions, among them a correction for the 400-year-rule, an Easter date indication, a star chart, a tourbillon, a perpetual calendar, a sidereal time indication, and, hold your breath, this watch was sold in 1989 for a cool four million Swiss francs (around Rs. 14 crores).
So, if you desire to be remembered by your descendants for eternity, save them the trouble of having to set their watch on March 1, 2100, bequeth them this watch. Since 1996, Svend Andersen makes a wristwatch with the strange name “Perpetuel Secular Calender”. The word “Perpetual” has been misspelt in the brand by Mr. Andersen. This Perpetual Secular Calendar is the only wristwatch that incorporates a correction for the 400-year-rule.
The tagline of Patek Philippe is a bit intriguing-“You never actually own a Patek Philippe. You merely take care of it for the next generation.”. However, if we know its history, its mystery gradually begins to unfold.