About Swiss watches
What makes a Swiss watch a Swiss watch?
Swiss watches are usually defined as watches that are totally manufactured in Switzerland or watches that have a Swiss movement. The Swiss government has proposed a rule that the Swiss share of production costs must be 60 percent for a product to be labelled "Swiss". However, the watch industry has proposed an even tougher rule, asking that 80 percent of the production costs be in Switzerland for a watch to be described as a Swiss watch.
Watches manufactured in Switzerland bear the designation "Swiss made" and the logo of the producer. The globalization has not affected the importance of this phrase.
Only when it is Swiss, may a Swiss watch carry the indications "Swiss made" or "Swiss", or any other expression containing the word "Swiss" or its translation, on the outside. A watch is considered to be Swiss if:
- it's movement is Swiss;
- it's movement is cased up in Switzerland;
- and the manufacturer carries out the final inspection in Switzerland..
What does a label "Swiss watch" mean for the customer?
"Swiss made watch" envokes a concept of quality that has been earned over the years. It includes the technical and aesthetic qualities of the Swiss watch. It encompasses both traditional manufacturing and advanced technology.
The Swiss are not the only watchmakers to manufacture high quality watches and are consistently faced with strong competition. The secret is in the unique infrastructure and innovation that makes them succeed in maintaining their leading position. The label is a result of painstaking efforts on the part of the watchmaking companies who are ultimately responsible for its reputation.
When were the first Swiss watches made?
Switzerland has been known as the center of the watch industry for more than 400 years. In 1541, reforms implemented by Jean Calvin banning the wear of jewels, forced jewelers and goldsmiths to turn into a new craft, watchmaking. By the end of the century, Swiss made and more specifically Geneva made watches were already being known for its high quality and let to the creation of the Watchmaker's Guild of Geneva in 1601.
The first Swiss watchmakers emigrated from France around 1550. Watchmaking in the Jura mountains remains indebted to a young goldsmith called Daniel Jeanrichard (1665-1741), who, for the first time, introduced the division of labor in watchmaking.
In 1790, Geneva was already exporting more than 60,000 watches. At the same time began the production of complicated watches and the introduction of special features such as the perpetual calendar, the fly-back hand and chronographs.In 1967, the Centre Electronique Horloger (CEH) in Neuchâtel developed the world first quartz wristwatch - the famous Beta 21. Since then, major technical developments followed without interruption: LED and LCD displays, Swatch, quartz wristwatch without battery, etc.
Despite the fact that Switzerland is so closely associated with watches, it was not always so. A beginning was followed by a slow but gradual rise to dominance. The dramatic turnaround about Swiss watches came about at the end of the 20th century.
Geneva remained the centre for design and marketing both before and after it joined the Swiss Confederation in 1815. But manufacturing spread to other areas as well, in particular to Canton Neuchâtel.
Swiss craftsmen also travelled abroad to study and to exercise their skills. Undoubtedly the best known is Abraham-Louis Breguet (1747-1823), born in Neuchâtel, who trained in Versailles and who settled permanently in Paris after a lengthy stay in London. He is regarded by some as the greatest watchmaker of all time. He invented or developed a number of important additions to watch design, including the tourbillon (a device which enables the gear train to function smoothly irrespective of gravity) and the self-winding watch (developing an idea commonly attributed to another Swiss, Abraham-Louis Perrelet (1729-1826)).
The Swiss, not only kept the foreground of innovation for Swiss watches, but they were also good at business and commerce and was backed by the Swiss banking system. It was very much an export oriented. There were Merchants developed who specialized in the Swiss watch trade that could report back on the eclectic tastes of other countries.
The superpowers in the watch development back in the day was Italy, Germany, France and the Netherlands. Swiss watch makers initially copied and pirated the thier designs and was able to produce them more cheaply. Thanks to more efficient production methods and a marketing strategy that worked, the Swiss watch industry started to grow and bagan making their own original Swiss watch designs.
The small components parts of the Swiss watch were made in villages around Geneva. People's homes or small workshops were called "homeworking". The components were returned to the craftsmen of Geneva for the finishing touches.
During the 17th century and going through the 18th and 19th, Asia was a vital market for Swiss watches. The Swiss started in Constantinople and later expanded to China, where the watches became popular and famous especially among the Qang dynasty in the middle of the 18th century. Exports to China peaked during this era only to collapse with the start of the Opium War.
Swiss watches were adapted to customer needs and tastes. Automatic Swiss watches were appreciated in Turkey and China with many of the watches having their own local touch.
In the 19th century, Swiss watches were made for India caleed Raja watches. This was done by manufacturing enamel portraits based on photographs that was sent to them.
The 19th century
The major breakthrough in Swiss watch manufacturing came in the early 1840 when Georges Leschot invented a series of machine tools that enabled him to manufactrure watch components. This new Swiss watches could be produced much faster and in greater numbers. The Swiss watch would also be more accurate and much cheaper. Leschot believed though that every part still had to be worked on by hand.
By the middle of the 19th century, Swiss watches would overtake the British both in sales and manufacturing and would become the world's top manufacturer.
The challenges continue: how to balance smallness of size with complexity of function, or low cost with high accuracy and reliability, and how to face up to competition from all over the world.
Who were the competition of Swiss watches back in the day?
In the middle of the 19th century, America started mass production of watch components that were precise and compatible with a wide variety of watches. The effect of this on the Swiss export market was devastating as the export of Swiss watches to the US dropped by 75% in a span of 10 years. The Swiss had to regroup and let them to embark on the precision machining of Swiss watch parts.
By the early 20th century, Swiss watchmakers, in order to make the Swiss watch more attractive to buyers, added extras such as calendars and stop watches. The first quartz Swiss watch was developed in 1967 but the Swiss failed to capitalise on the new technology opening the doors for Japan and the US to improve on the discovery.
The Swiss diverted most of thier effort in improving mechanical watches which proved to be another blunder as it destroyed the Swiss watch industry in the mid 1970's. The bottom fell out of the market for traditional watches. Switzerland was no longer a major player as far as watches were concerned during this time but they fought back in an unusal and unexpected way. They called in a business consultant and came out with an idea that revolutionized the Swiss watch industry.
The consultant brought up the idea of marketing the Swiss watch as a fashion statement. The cheap electronic Swiss watch called Swatch has sold millions and put the country back to the top of the world's exporters in 1995. The success of the Swatch is credited with turning around the fortunes of the Swiss watch industry as a whole. It boosted confidence in Swiss watch making and showed the Swiss how to sell their products.
What are some of the popular brands of Swiss watches today?
Some of the leading brands of Swiss watches are:
Why are Swiss watches famous?
The Swiss watch industry is the largest in the world. Swiss trains and buses are always on time and in general Swiss residents are punctual and reliable. Switzerland has long been associated with high-quality watchmaking. Swiss watches are the country's third biggest export after the chemical and engineering industries in terms of value.Switzerland owes it success not only to the high-quality of its output, but also to the wide range of the watches it produces, in terms of both technology and appearance. Nearly 90% of the watches made in Switzerland are electronic, but mechanical watches, the remaining 10%, account for over half the exports in terms of value. Some of the watches at the upper price range are among the most complex in the world. Swiss wathces range from sober classic, daimond studded, to cheap and cheerful. The increase of the productivity, the interchangeability of parts and the standardization progressively led the Swiss watch industry to its world supremacy. Since more than four centuries now, tradition, craftmanship, high technologies and permanent innovation have allowed Swiss watchmaking industry to keep its leadership in the world watch market.
What are the different types of Swiss watches?
Battery, quartz or mechanical (hand-wound)
Digital Swiss watches are powered by an ultra-small watch battery. You can usually find it by the check out couner of many electronic stores.
Quartz Swiss watches source of energy consists of a miniature battery which lasts several years. The time is divided by a quartz oscillator which is made to vibrate by the energy supplied by the battery. Quartz watches are extremely accurate thanks to their high frequency of vibrations (32 kHz); their annual variation is only about one minute per year, equivalent to less than a second a day.Quartz Swiss watches are analog timepieces that run on a tiny, vibrating, electrified quartz crystal. They keep extremely accurate time (within a minute each year).
The traditional mechanical Swiss watch is made up of about 130 parts assembled in the three main parts which are the source of energy, the regulating parts and the display. The number of component parts is much higher in so-called complicated watches (date, phases of moon, fly-back hand, etc.). The "ébauche" (about 60 parts) fitted with the regulating and certain other parts, forms the movement, in other words the internal mechanism of the watch, which makes it possible to maintain a constant tension in the spring once it has been wound manually or automatically (by movements of the wrist) and to regulate the display by means of the hands (hours, minutes, seconds). A Swiss watch is said to be finished when the movement has been fitted with a dial, hands, and case. Mechanical Swiss watches are powered by a complex array of gears and springs. These watches can command a hefty price as a result of their superior craftsmanship. Unfortunately, the ancient art of hand-wound watchmaking remains imperfect. Mechanical watches lose about an hour a year and must be wound regularly.
Analog, digital or analog/digital
In an analog quartz Swiss watch, the heart of the watch is the integrated circuit, made up of a large number of electronic components grouped together on a base of only a few square millimeters. An analog Swiss watch has a face that holds hour and minute hands, and either numbers, markers or Roman numerals that display a 12-hour day. It is considered the more formal, classic watch type, and is perfect for business, dates and formal events.
Digital Swiss watches either have an LCD (liquid crystal display) or LED (light emitting diode) face that displays the time in numeric form (for example, 2:50). They're considered very casual.
Analog/digital Swiss watches have both an analog and a digital face. They're utilitarian and can be worn to work and during your daily routine.
What are the different types of Swiss watch crystals?
Swiss wathces that has this transparent cover protects the watch face. It can be made from plexiglass, mineral (traditional) glass or synthetic sapphire -- an ultra-hard, clear, man-made crystal.
Plexiglass is the cheapest of Swiss watch "crystals." It's the least likely to shatter, but the most likely to scratch. They are the least expensive and commonly found on vintage watches and select modern watches. These crystals scratch easily, however they are cheap to replace and easy to buff scratches. Plastic crystals offer a "warmer" appeal. Reissues like the Tag Heuer Monaco are often fitted with acrylic crystals to maintain the appeal of the original.
Mineral glass, on the other hand, is more likely to shatter, but less likely to scratch. Mineral materials are between plastic and sapphire in cost and scratch resistance. It is virtually impossible to tell the difference between mineral and sapphire without taking a steel knife to the crystal to test it (not recommended!). Mineral crystals are more commonly found on non-Swiss watches.
Synthetic sapphire costs the most, but it's the most scratch-resistant. Synthetic sapphire breaks quite easily and are the most expensive and the most scratch resistant. It can only be scratched by diamonds and other surfaces with a mineral hardness of 10. They are generally over $100 to replace and basically impossible to buff any scratches out. Since they are so hard, they are more likely to shatter on heavy impacts than a plastic crystal. As more consumers understand the durability of sapphire, more come to expect it on their watches. The vast majority of modern Swiss watches utilize a sapphire crystal.
What kind of maintenance does a Swiss watch need?
Swiss watches that are mechanical and automatic should be cleaned and serviced every three years to ensure trouble-free time keeping. The moving parts of quartz Swiss watches also need maintenance, as they are not under tension and any small, foreign particle is sufficient stop them.
Where fitted, the battery needs to be changed when drained. This is the time for routine maintenance. Apart from changing the battery, digital quartz watch need no routine maintenance. Where water resistant seals are fitted, cleaning is required less often, however seals must be changed whenever the case back is removed. Otherwise they should be changed annually and resistance checked using pressure equipment, through the manufacturers' agent.
It is worthwhile remembering that regular exposure to chemicals, or sea water, can damage straps, plated cases and bracelets and a solid metal or specially constructed material is recommended if regularly used in these conditions. Cosmetics and perfumes can also cause damage if directly applied to plated dials and straps.
What is the difference between a Swiss chronometer and chronograph watch?
A Chronograph watch is a timepiece equipped with additional time measurement functions independent of normal time-telling. A chronograph is a watch that has a stopwatch function. It will have two or three additional registers. The simplest chronographs have a register for 30 minutes, and a center-mounted second hand. The popular ETA Valjoux 7750 times up to 12 hours. Most quartz chronographs also time tenths of a second, something a mechanical can not easily do and most of us will not need.
A chronometer is a watch which has passed a test given by the Contrôle Officiel Suisse des Chronometres, or COSC. The COSC is an official Swiss government agency which tests watches to ensure that they fit within a narrow-but-usually-obtainable window of acceptable error (i.e., the rate in all positions falls into the range of -4 seconds/day to +6 seconds/day). While some watch companies tout their products as having a COSC certificate, it really is not that difficult to pass the test, and over 95% of the watches submitted pass. Another factor to consider is that the COSC does not test watches as they are sold in the store, but movements fitted with a temporary case, dial and hands. In addition, the COSC certificate cannot say anything about how the movement was handled after testing.
A Chronometer Swiss watch is a high-precision timepiece which movement, after rigorous testing, has received an official timing certificate from an official timing bureau.A chronometer is watch that has passed a series of tests, and is a superior timekeeper. To become a chronometer, the watch movement must pass 15 days of severe tests. The accuracy of the movement is checked in 5 different positions at varied temperatures. This simulates conditions under which the watch might be worn. The Swiss watch must average between +6 and -4 seconds per day in order to earn the certification.
Swiss Watches providing additional measurement functions to the hours, minutes and seconds are referred to as "Complications". The best-known complication watches are calendar watch, the most common of which display only the date. There are also chronographs with a center seconds hand which can be started, stopped and brought back to zero using one or two push-button on the side of the watch. Other additional functions include second time zone, alarm, moonphase, repeater, perpetual calendar, etc.
What does the jewels mean in terms of Swiss watch movements?
The jewels are synthetic sapphires or rubies which have been drilled, champfered and polished to serve as bearings for gears in watches, reducing friction or mechanical parts to a bare minimum.
Generally speaking, one may say that a simple mechanical watch (hours, minutes and seconds hands) should include at least fifteen jewels located in the places most subject to wear due to friction. It should be fitted with a shock-absorbing system on the balance, a good quality balance-spring and an unbreakable spring.
Only those pieces of the movement which are between the mainspring and the escape wheel are candidates for jeweling, as these are the movement parts that experience the large forces or relatively high speeds of the mainspring or escapement. Other components, such as the motion works (i.e. hour and minute wheels), calendar mechanisms, and winding train are not under this constant stress, and thus arguably do not need jewels.
Automatic winding movements will add about 4-8 jewels to help most efficiently transfer the relatively small rotor forces into winding the mainspring. Some chronograph Swiss movements used today are modular in construction - meaning that a plate containing the chronograph works is grafted onto a basic timekeeping movement. Since the original timekeeping movements were not always designed with this in mind, it becomes critical for the add-on module to add as little "drag" as possible - which may indicate use of jewels for their low friction properties.
As a historical note, there was a "jewel craze" about 50 years ago, where manufacturers, under the belief that the public thought more was always better, came up with 75 or even 100 jewel movements. Most of these jewels were not functional in any way, and the results looked ludicrous to an informed eye.
In other words, more jewels does not neccessarily mean that a Swiss watch performs better. Some of the jewels are just for aesthetics and actually serve no functional purpose.
Does magnetism affect the performance of a Swiss watch?
It doesn't usually affect digital quartz Swiss watches, but it can affect analog Swiss watches, which use a tiny electric motor to turn the hands. Powerful magnetism can affect the performance of this motor. Although analogue watches may gain time, lose time, or even stop under the influence of powerful magnetic fields, they will usually return to normal time-keeping as soon as they leave the source of magnetism. Avoid putting your watch near medical equipment, headphones, speakers, or refrigerator door magnets.
Electric mixers and blenders and a wide range of other electrical equipment may also have strong enough magnetism to affect timekeeping. Generally, a Swiss watch would have to be within inches of a magnetic source in order for it to be damaged.
What does water resistant Swiss watches mean?
A Swiss watch marked as water resistant without a depth indication is designed to withstand accidental splashes of water only. Do not submerge such a watch. Higher levels of water resistance are indicated by increasingly higher acceptable depths, usually indicated in meters.
Depending on the cases, Swiss watches are tested at different pressures and during variable periods of time. Exceptional pressures, as when diving, may exceed those limits, so if you are a keen diver you will need a watch that can tolerate that pounding. There are a variety of ways to make a watch water resistant. All such watches use rubber gaskets or "O" rings to seal the case back. A watch with a back that screws onto the case provides a higher degree of water resistance.
It is not recommend that you wear your Swiss water resistant watch to a hot shower, suana, or hot tub. The extreme heat causes the metal parts to expand faster than the rubber gaskets. This creates minute openings that can allow small openings to penetrate the watch. One should never expose a watch, even a diver's-rated watch, to any of these conditions as the o-ring gaskets can degrade and/or fail, allowing water to enter the watch case and ruin the watch's expensive internal components (dial, hands, movement, inside aspect of a coated crystal, etc.)
Some crowns (the "winding stem") actually screw into the case to further increase water resistance. Please note that we do not recommend swimming or diving with your watch unless it has a screw-down crown (also known as ‘screw-lock’ or ‘screw-in’ crown) and is water-resistant to at least 100 meters.
After swimming or diving in salt water, immediately rinse the watch in a stream of fresh water. If your watch has a rotating bezel, turn the bezel several times while rinsing it. This will prevent salt buildup and corrosion of the bezel ring.
How often should I wind my mechanical Swiss watch?
There are two types of mechanical watches which differ in how they accumulate power.
Some mechanical watches require that the wearer wind them in order for the mainspring to store power. This is done by rotating the crown (winding knob) at least 30-40 revolutions (when the watch is fully unwound or stopped). Once resistance is felt on the knob, winding attempts should cease, and no benefit is gained by "adding just a little bit more force" to the winding knob, and may cause damage. Once fully wound these watches will typically run for a total of 30-40 hours (the "power reserve"). If the watch can not be wound more than a few turns, if any, and is not working once the crown is parked, then service is required.
A second type of mechanical watch is an "automatic," meaning that the watch movement has an oscillating weight that revolves when the wearer's wrist and/or arm are in motion, and the mainspring is wound without the need to wind the crown. Most automatic Swiss watches that are worn for 8-10 hours daily require no winding by the wearer at all, as the this duration of wear will store up to 20 hours of power reserve - enough for the watch to power itself during the evening and night. However, if an automatic mechanical watch is infrequently worn, then it will be necessary for the wearer to wind it at least a dozen or so times in order to store sufficient mainspring power for the watch to function accurately. If the automatic is not worn regularly, consideration can be given to the use of an "auto-winder," a machine that simulates the motion of the wrist and arm. Utilizing an auto-winder on an automatic watch can keep the watch functioning more accurately over time, and reduce the need for more frequent servicing. Watches-Swiss.com offers an extensive list of mechanical and quartz watches for your dicerning taste.
Do I need to break in my mechanical Swiss watch?
There should be a short "burn in" period that can be expected after purchasing a brand new Swiss mechanical watches. It should not pose a problem as the watch should be able to take care of itself. A brand new mechanical Swiss watch that has been recently purchased may have been sitting in the showcase for quite some time. This causes the oils and lubricants to pool into certain parts of the movement therefore unevenly distributing the lubricant. It takes an average of 30 to 60 days of use to be able to distribute the lubircants into its proper place. Aside from the distribution of oils, constant use wil wear out minute imperfections in the gears and after some time use, will make the watch more accurate and precise.
What are some other materials used as Swiss watch cases?
The standard gold and stainless steel, high-end Swiss watches are often made of platinum or titanium.
Platinum is a very heavy metal, and gives a shiny white metal appearance. Unlike gold, pure platinum is fairly hard and resistant to scratches (similar to hard stainless steel). For this reason, it is often used in 95% purity (i.e. Pt 950). However, raw platinum is more expensive to use, not only because of its rarity, but also because it is used in higher purities and requires more effort to work into a final shape.
Titanium is a relatively light-weight metal, with a hardness exceeding that of most steels. It also has a poor heat transfer capability, which means that it won't carry heat away from your skin as quickly as steel or aluminum (i.e. it will feel warmer to the touch - sometimes you'll see claims that titanium "remains at skin temperature" - this is technically incorrect, any more than a small piece of wood stays at skin temperature). Several varieties of titanium are available. Titanium has some interesting mechanical properties: it can "rip" when cut so it is difficult to machine, and two pieces of titanium pressed together can "weld" themselves together. This latter property is why it is important that watches with titanium cases and backs have the casebacks removed periodically - the threads can actually rip out of the case if left undisturbed too long.
What is the rule in changing the dates in a Swiss mechanical watch?
It is important to remember that you do not change the date when the hour hand is in between 9 and 3. The Swiss watch mechanism that is responsible for incrementing the date (wheel) does so by gradually accumulating (or building up) tension. At 12am, the accumulated tension is released and quickly applied to rotating the date wheel, hence the instant flip. I believe this mechanism accumulates tension starting at 8pm, continuing to do so until midnight, hence the need for the "8pm-2am recommendation". The safest is to simply not change the date if the time shows between 9:00 p.m. and 3:00 a.m on any watch.
If you pick up a watch and the time shows between 9:00pm and 3:00am simply wait to change the date, or change the time to 6:00am and then change the date - no big deal. It actually becomes a habit after a while.
With some watches you can damage the date change mechanism. The watch will probably keep running, but the date won't change anymore.
How should I care for my Swiss watch case and bracelet?
Metal bracelets should be washed carefully in water. Use a soft toothbrush to gently brush away the dirt if really dirty. Rinse with water and and dry carefully with a clean soft cloth. If your watch is not water resistant, be careful not to get water on the case. Cases should be cleaned by a moist cloth and dried carefully.
As much as possible, Swiss watches with leather straps should be slightly loosened in the summer, when they may absorb perspiration. The tight strap not only prevents the passage of air over the strap undersurface but can also cause a perspiration rash on the wrist. If the strap ever becomes wet with perspiration, wipe it dry with a soft cloth.
When you take off your watch, leave it in a well-ventilated spot. Never put it in a sealed container when it is still damp with perspiration. Avoid leaving your watch in direct sunlight. The strap color may fade.
What kind of special care should I give my Swiss watch?
Avoid undue shocks (such as dropping on hard surfaces). The normal shocks caused by sports like tennis or golf present no threat to quartz watches.
Temperature Extremes: Quartz Swiss watches are much less affected by extremes of temperature than mechanical watches, and are designed to keep good time if worn on the wrist for eight hours a day with ambient temperatures between -10 degrees and +35 degrees Celsius. If removed completely from the wrist, your watch may lose time during the winter, but will return to normal accuracy as soon as you start wearing it again.
If your Swiss watch is stored at temperatures outside the normal range (as low as -10 degrees Celsius or as high as +60 degrees Celsius) the electronic components may cease to function normally.
The response time of liquid crystals used in the displays on digital watches at temperatures below freezing is slow, and they tend to look very dark at high temperatures, but normal performance returns at normal temperatures.
Battery life can be significantly reduced at high temperatures (above 40 degrees Celsius), and battery fluid may even leak out.
Does a Swiss watch need periodic maintenance?
As a Swiss watch ages the lubricants start to break down and the gears shift ever so slightly, and the accuracy of the watch will decline as well. The accuracy may be compensated by performing a couple of regulations over the course of a few years. However, ultimately a complete overhaul will be required.
This maintenance will help seal and protect the watch movement against air, dust, and moisture, which over time, can penetrate the watch case seal, and prevent the watch movement from functioning properly.
There are a few methods of thoughts to the frequency of service. Some say that a service should be done every 2-3 years as the manufacturer suggests. Others subscribe to the "if it ain't broke, don't fix it" rule and will only send it into the manufacturer once the watch stops working - which could be many years. We suggest a middle ground, that the watch go in every 5 years or sooner if you notice something amiss.
Anything longer than 5 years will create undue stress on different parts and end up costing more to replace those components. A complete overhaul entails disassembling the movement, inspecting each component, replacing any damaged components, cleaning each part, lubricating, reassembling, adjusting and regulating the movement.
What does power reserve mean for a self-winding mechanical Swiss watch and how does it work?
The power that is generated by a Swiss self winding mechanical watch is generated by the wrist movements of the wearer. The watch will usually have a power reserve of 44 hours on a fully charged or wound watch. 10-12 hours of normal wear by the user should be able to generate power for 20 hours or more. This ensures that the Swiss watch will run continuosly througout the night. On the other hand, if a watch has not been worn for several days, its power reserve will run low and eventually stop the watch from running. It is best to manually wind the Swiss watches' crown15 times for best results.
It is also an indicator that displays the approximate number of days or hours left on the current state of mainspring wind. This typically cannot be done by a simple gear train, since a Swiss watch is wound from the center arbor of the barrel, and the power is removed from the outer rim of the barrel. Therefore, a gear train that can act as a differential is required to read out the difference between the arbor position and the barrel rim position.
This can be a very useful complication, as it lets one know whether a watch is wound before putting it on.
What is a perpetual calendar Swiss watch?
A perpetual calendar is the most developed form of the simple date window on a typical watch. It keeps track of date, day-of-the-week, (sometimes weeks), months, year, leap years, and sometimes even centuries.
The term perpetual calendar is also used in watchmaking to describe a calendar mechanism in a watch that displays the date correctly 'perpetually', taking into account the different lengths of the months as well as leap year's day. In other words, a Swiss watch with a perpetual calendar will display the correct date and takes into account months with less than 31 days and leap years.
The internal mechanism will move the dial to the next day.
Due to the very complex rules of the Gregorian calendar, that includes different lengths of months and leap years every four years, a common calendar wheel turn several times per second for four years.
Some less complex calendars are also available:
- Semi-perpetual calendars, which requires an adjustment on leap year day only.
- annual calendars which only require a user adjustment once every February
- "triple date" calendars, which contain month, day, and date - but need to be manually advanced at the end of each (short) month
Experts say that the inconvenience of resetting the date on a true perpetual Swiss watch is the reason why the watch winder was invented.