The desire to know is natural to good men - Leonardo da Vinci
International Watch Company - Da Vinci Perpetual Calendar
- a brief introduction -
Ratskunk - September 2001

In 1985, the International Watch Company introduced the automatic chronograph Da Vinci with perpetual calendar and moon phase indicator. Excepting a visit to the watchmaker in February 2100 due to the vagaries of the Gregorian calendar*, the Da Vinci Perpetual Calendar will measure the minutes, months, phases of the moon and years without interruption or adjustment until the year 2499. In Schaffhausen the Da Vinci is regarded as the watch event of the 1980s and for this Da Vinci owner, it is the watch event of a lifetime.

My Da Vinci

I was shocked! The first time I saw the IWC Da Vinci I was shocked in the way I was shocked upon seeing for the first time Les Demoiselles d'Avignon in the Museum of Modern Art - shocked in the way I was shocked upon first listening to Free Jazz. The lugs, the pushers, the Merlin mechanics - I loved it and quietly and quixotically dreamt of owning the watch. Fast-Forward Many Years --> Finally...the stars align and I own the watch. My Da Vinci is the Ref. 3750 in stainless steel with a black crocodile strap with folding buckle and is my daily timepiece.

Radical 20th Century Art - beautiful and disturbing:
Les Demoiselles d'Avignon
Picasso - 1907
Free Jazz
Ornette Coleman - 1960
My Da Vinci on "White Light"
IWC - 1985
The Da Vinci Perpetual Calendar
Kurt Klaus
Father of the IWC
Perpetual Calendar
Leonardo da Vinci
Father of the

The job of a perpetual calendar is to measure the days, months and years, allowing for the vagaries of the Gregorian calendar i.e. the sundry lengths of the months, years and centuries. The Gregorian calendar, decreed in the papal bull Inter Gravissimas by Pope Gregory XIII in 1582, among other revisions to the Julian calendar, set forth the Leap year rules currently adhered to in the modern era. The Gregorian Leap Year adds a day - namely February 29, to the calendar every four years, excepting that every 100 years the Leap Day is neglected, with the further exception that every 400 years, February 29 is retained - the Da Vinci Perpetual Calendar accounts for all except the 100 and 400 years exceptions.

Inter Gravissimas
Date Program Disc -
The Metal Brain

The IWC perpetual calendar, master-minded by Kurt Klaus, takes the Gregorian calendar in stride - aside from a visit to the watchmaker in February 2100 - and does so solely by means of the watch crown. Whereas traditionally, independent pushers are required to set the day, date, month and moon phase, the Da Vinci's calendar functions are integrated thus allowing the setting of the calendar by the crown alone, permitting the Da Vinci owner to advance the calendar as simply as one would advance the date on a watch with a quick-set-date feature. Please refer to the references below for detailed summaries of the perpetual calendar's operation. The Grande Complication by Manfred Fritz gives a description of the perpetual calendar mechanism in murderous detail that most will find pleasant suffering.

Other IWC Perpetual Moon Phase  Watches
Further reading on the IWC Perpetual Calendar:
"The IWC Perpetual Calendar Mechanism" by Walt Odets - TimeZone Horlogium 1998
"The Amazing Da Vinci Moonphase" by Michael Friedberg - IWC Collectors Forum Articles Section 2001
Da Vinci Reference 3750 Technical Specifications

The movement in the current Da Vinci Reference 3750 is the IWC C. 79261 based on the Valjoux 7750 chronograph movement with an in-house perpetual calendar module developed by Kurt Klaus. The IWC C. 79261 is a 30 mm diameter, H 8.8 mm, 39 jeweled, 28,800 vph. automatic movement with a power reserve of approximately 44 hours. The watch's water-resistance is rated at 30 meters.

movement.jpg (4358 bytes)

The case is 39 mm in diameter with a height of 14.3 mm, though the watch looks much smaller on the wrist - the sense of height is attenuated by the tiered construction of the case and crystal. The crystal is domed plexiglass and the Ref. 3750 has a screwed-down crown and pressure shut case-back. The chronograph start/stop button is at 2 o'clock and the reset button is at 4 o'clock. The case lugs measure 20 mm across.

The Da Vinci is supplied with a wax-sealed vial containing a replacement century slide for the twenty-third, twenty-fourth and twenty-fifth centuries. A visit to the watchmaker will be required in January 2200 to have the new century slide installed in the watch - then mark your calendar for 2499 for your next IWC check-up.  

The dial layout is as follows: the moon phase indicator is at 12; small seconds at 9; date indicator at 3 consisting of two rings - the odd dates on the outer ring, even dates on the inner; the months indicator ring at 6; the day of the week indicator at 9 and century-decade-year indicator between 7 and 8. The chronograph has center-seconds hand with a 30-minute counter and 12-hour counter at 12 and 6 respectively.

The month, date, day of the week hands are Feuille, the chrono center-seconds Breguet and the minute counter, hour counter, small seconds are Baton and the hour and minute hands are luminous-coated Baton hands. Luminous-tipped Baton markers mark the hours. The only wording on the dial unrelated to the measurement of time is IWC Schaffhausen located beneath the moon phase and Swiss at 6.

The Da Vinci Family

The first Da Vinci was introduced in 1970. In 1985 the Da Vinci Perpetual Calendar was introduced. In 1986, a Da Vinci with a high-tech ceramic zirconium oxide case was released and then in 1988, the Small Da Vinci - in 1995 the Da Vinci split-seconds chronograph was introduced - followed in 1998 by the stainless-steel Da Vinci and in 1999, the Da Vinci Tourbillon.

Original Da Vinci
IWC Cal. 2002
Lady Da Vinci
Early 1970's
Ceramic Zirconium
Oxide Case
Small Da Vinci
Ref. 3736
Split-Seconds Chrono Da Vinci Tourbillon
Ref. 9267
The Da Vinci Four Seasons Tourbillon

The hand-wound Da Vinci Quattro Stagioni (Four Seasons) Tourbillon Reference 3752 is a limited edition of twenty pieces introduced in 1999. The solid gold dial, painstakingly hand engraved by IWC master engraver  Wolfgang Siegwart, features four allegorical figures representing Spring, Summer, Autumn and Winter - a fitting canvas for a perpetual calender marking the passage of time and seasons.

The Limited Edition Platinum Blue Da Vinci

2002 introduced the limited edition, 500 pieces, Platinum, blue-dialed Reference 3754 Da Vinci Rattrapante. Like the blue-dialed platinum Ref. 3251 and Ref. 5002, the platinum Da Vinci is paired with a blue crocodile leather strap. A timepiece this beautiful only comes around once in a blue moon. If you are not feeling blue, you can opt for the platinum silvered dial version on black croc strap introduced in 2003.


The Da Vinci Perpetual Calendar, with its little helmeted chronograph pushers, the love-em or hate-em lugs, its revolutionary calendar, is more art than watch...more magic than mechanics. The Da Vinci is a timepiece you purchase because you're spellbound, not because you need a watch with a perpetual calendar, a moon phase indicator, a chronograph and IWC on the dial - thus I cannot recommend the Da Vinci in any practical manner  - the Da Vinci is an affair of the heart - and when deciding on a Da Vinci the heart is judge and jury.

Additional Reading and Viewing:
Leonardo Da Vinci - Kenneth Clark
Penquin Books 1993
128 pages - ISBN 0-1401-6982-2 
The Grande Complication - Manfred Fritz Edition Stemmle Schaffhausen 1990
240 pages - ISBN 3-7231-0437-1
Mona Lisa - Leonardo da Vinci
Oil on Wood 1503-1506
Louvre, Paris
Ratskunk Articles
IWC Literature - 3 Books
IWC Da Vinci Perpetual Calendar - a brief introduction
Manufacture Literature - AP-Lange-Breguet-PP-VC - a little peek
*a visit to the watchmaker is required in 2200 to exchange the century slide.