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What is a Chronometer? Who invented the tourbillon? In our Watch Lexicon, which was created in cooperation with our trained watchmaker Daniela Feldhusen, you will find information, facts and answers - from A like ANKER to Z again ZUGFEDER.


The anchor (also known as balance spring) is the clock or the regulator in the watch. It briefly holds the clockwork and then releases it again, and this is heard as ‘tick-tock’. The anchor (balance spring), together with the balance wheel and lever forms the so-called escapement.


Together with the watch-stem and the crown, the main spring is stretched, thereby enabling the hand setting for time and/or date.

Automatic watch

With an automatic watch the spring is wound with the help of a rotor or balance weight, which rotates with regular wrist or arm motion. The power reserve is generally about 40 – 45 hours.

Breguet spring

The Breguet balance spring was invented by Abraham-Louis Breguet. With this particular spring the last rotating hand is bent upwards. Until his invention they were placed flat next to each other. The upwardly curved hand enables the watch to breathe more evenly. A watchmaker would say: “the spiral breathes evenly”. Currently, most watches feature the Breguet spring as it guarantees a better accuracy of the watch, and it is also easier to adjust the watch. 


The Chronograph is the watch’s stopwatch function. In most watches the stopped time is shown in seconds/minutes/hours with the help of dials. 


A watch known as a chronometer is a highly accurate watch, and this watch must not run slower than 2 seconds of faster than 8 seconds per day. The Chronometer Certificate, also known as the Movement Certificate, is issued by the independent Chronometer Institute (COSC: Contrôle Officiel Suisse des Chronomètres). Each individual timepiece spends two weeks at the Institute and is tested for accuracy. Each certificate is unique and is individually numbered.

The German Chronometer Institute is based in Glashütte, near Dresden.

Co-axial escapement

In this case the anchor has not two but three anchor forks. The contact between the anchor and the anchor wheel is very brief and punctual. This process creates less friction and the intervals of the oscillator are significantly longer. Omega holds the patent for the co-axial escapement. 

Rapid date adjustment

This function enables the rapid adjustment of the date, without altering the position of the watch’s hands. This is done through the watch-stem, which has several positions. In some watches the rapid date adjustment is done through the pushers (for example Patek Philippe Nautilus Chronograph).


In general there are two pushers on a chronograph. The top one is for the Start/Stop function. If you press the bottom pusher the stopwatch hand is reset to zero. Please also refer to: screw-down pushers.

Perpetual calendar

A perpetual calendar is a so-called complication. The mechanism is so refined that one does not need to adjust the date as long as the watch is running. The length of the month is exactly calculated, also during leap years. The world’s first wristwatch with a perpetual calendar dates back to 1925 by Patek Philippe. By the way, the perpetual calendar will have to be reset by watchmakers in the year 2100; in this particular year February 29th will not occur.

All fine manufacturers who want to maintain their reputation offer a perpetual calendar watch as part of their collection. For example: Patek Philippe, Audemars Piguet, Jaeger LeCoultre, Vacheron Constantin, A. Lange & Söhne, Breguet.


With this particular chronograph function / feature you can return to the zero position with just one click on the button. As you release the pusher the stopwatch immediately continues. The fly-back function was patented in 1946 by Dubey & Schaldenbrand for pilots so that they could measure intervals without any delay.

This function one can find, for example, in the Blancpain Fly-Back.

Foudroyant (french for lightning)

Watches with a ‘foudroyant’ carry a subsidiary dial where the split second (1/8s) can be read. The foudroyant function is usually found in ‘rattrappants’, or trailing pointers. The pointer on the subsidiary dial moves forward in 1/8s increments.

Power reserve

This term refers to how long a watch can run. A hand-wound watch is usually equipped with a barrel and runs accurately between 30 and 35 hours. An automatic watch with a barrel will run for about 40-45 hours. There are currently wristwatches that can run for far longer due to multiple barrels. An example is the Patek Philippe ’10 Days’, which houses four multiple barrels.

Blewed screws and hands

In the 16th Century the hands of a watch were blued for the first time, in part to improve the resistance of the hands, and in part for aesthetic reasons. A watch with blued hands was considered a sign of the utmost craftsmanship as the manual creation of these cornflower hued hands and screws required a lot of experience and skills.

The ‘bluing’ process is a thermal process whereby the hands and screws are evenly heated and made to glow incandescent before quenched by cold. With the uniform heating the blue color is created. If the material is either heated for too long or not long enough then the material is rendered useless.

Manual wind

The tension spring is wound by turning the crown and therefore the watch-stem. In manually wound watches a resistance when turning the crown indicates that the tension spring is wound tight. A manually wound watch should be wound daily.

Helium Valve

A helium valve is used for diving watches. It was invented for professional divers who descend into the depths of the sea in a helium capsule / diving bells. The extreme pressure inside the capsules forces the helium molecules to penetrate into the watch. When the divers ascend to the surface again, the helium expands so strongly that without the helium valve the watch would explode. The helium valve allows the helium to escape as divers resurface. An example is the Rolex Sea Dweller–Deep Sea.


The escapement consists of the anchor wheel, the anchor and a lever with a spiral spring. The escapement regulates the motion of the watch.


The caliber indicates the different sizes of the watch. The caliber number will often designate the type of watch of the manufacturer. For example, Kaliber 240 by Patek Philippe is the thinnest automatic watch and has been produced since 1977. 

Small Second

The small second is most often found on the watch-face at 6 and is a sub-dial for the seconds.


What is a Chronometer? Who invented the tourbillon? In our Watch Lexicon, which was created in cooperation with our trained watchmaker Daniela Feldhusen, you will find information, facts and answers - from A like ANKER to Z again ZUGFEDER.


The bezel is part of the watch and is the ring around the case that holds the glass case in place. Bezels can also be rotated; for example, on a diving watch (Rolex Submariner) to set the dive time, or on a time-zone watch (Rolex GMT Master) to set a second time-zone. 

Mechanical watch

A mechanical watch – contrary to a quarz watch - is driven by the mainspring and not by a battery.

Moon-phase Calendar

The lunar cycle is one of the many complications. A sub-dial in the shape of a semi-circle indicates the current moon. The lunar cycle is also found in perpetual calendars.

Acrylic glass

Until the 1970’s acrylic glass – also known as Plexiglas – was integrated in wristwatches, the main disadvantage being that it scratched easily. Yet unlike sapphire glass, acrylic glass can be polished. When it breaks the material does not splinter and it therefore cannot damage the dial or the hands of the watch.


The pulsometer is a scaling on the dial that enables you to measure the pulse with the second hand, and it is also known as the ‘doctor’s watch’. An example is Patek Philippe.


A battery-powered watch.

Rattrappant (french for overtaking)

This is also known as a double chronograph, and is an additional function to the chronograph, which enables it to stop at intervals. There are two overlapping stop-seconds hands on the dial and three pushers on the casing. By pressing the additional pusher one of the seconds hands stops and the other one continues. In that way multiple intervals can be measured. When the pusher is pressed again the first seconds hands jumps forward to catch up with the other. This function was re-introduced to the market by Blancpain in 1989 and is making a true come-back with many watch manufacturers.


The repeater is an acoustic time display. This complication was designed to keep time at night – without having to light a candle or petroleum lamp. Through various beat intervals one can distinguish between a full hour, quarter of an hour or even minutes (Minute Repeater).

For example: at 11.45 the watch will strike eleven times for each hour, and three times for the quarter hours. By moving a lever at the casing this function is activated. An example of such a watch can be found at Breguet.


The running rotor is a Rolex invention. The first functional automatic watch with a rotor is the Rolex Oyster Perpetual, dating back to 1931. In automatic watches the rotor is part of the winding mechanism. Unlike manually-wound watches, the rotor is set in motion as the hand or arm moves and it thereby winds the mainspring. Should the watch have been set aside or not worn then the mainspring will need to be re-charged through the crown in order to re-start the watch. By wearing the watch the mainspring is always wound and the watch is more accurate.

Saphire glass

Sapphire glass is characterized by its extreme hardness/rigidity (9 Mohs) and its resistance to scratching. The glass, however, cannot be polished.

Screw-in bottom

So bezeichnet man den Boden einer Uhr, der mittels eines Gewindes auf das Gehäuse aufgebracht wird. Schraubböden werden häufig bei wasserdichten Uhren verwendet. Beispiel: Rolex

Screwed crown

Using a tube the crown is firmly screwed into the casing. To ensure that no water can enter the watch, the crown is always screwed in with waterproof watches. Rolex was the first watchmaker to successfully apply screwed crowns in the Channel swimming watch for Mercedes Gleitze.

Skeleton Watch

To give a watch a delicate and ornamental appearance parts of the watch are cut so that certain parts of the watch are artfully displayed. The craftsmanship can be admired through the watch crystal on both the front and back of the watch. 

Spiral Spring

The spiral spring sits on the barrel of the balance and is part of the escapement. The watch is regulated along the length of the spiral spring. The spiral spring is also responsible that the balance swings regularly. If a watch is too fast or too slow, it can be regulated by adjusting the spiral spring length.

Jumping hour

The jumping hour is a digital display in the mechanical part of the watch. At each full hour the hour jumps by a digit. The first watch with a jumping hour was invented by Friedrich Gutkaes, the father-in-law of Adolf Lange, and is still on display at the Semperoper (Semper Opera) in Dresden, Germany.


The jewels (stones) typically found in a watch are synthetic rubies and these serve to keep the friction between the pivots and wheels to a minimum.


The tachymeter is found on stopwatches. It is made visible by a disc around the dial. The tachymeter was developed to measure speed (for example of cars at speed racing). The most famous tachymeter watches are the Rolex Daytona and the TAG Heuer Steve McQueen.

Diving watch

A watch in known as a diving watch is it is waterproof for over 20 Atm. Diving watches always have screwed crowns and screwed-in bottoms/backs. The watch is case is stronger and the crystal is thicker so resist the water pressure. Diving watches have a one-way rotating bezel to adjust the compensation time. The bezel can only rotate one way so that the diver cannot accidentally adjust the time to his or her disadvantage.

Tourbillon (french for whirlwind)

The tourbillon was invented by Abraham-Louis Breguet. In the tourbillon the escapement is found together with the anchor wheel, the anchor, balance and spiral spring. The tourbillon rotates on its own axis every minute. This motion serves to compensate for any variations of the balance and the balance spring that occur due to gravity. Only those with the finest watchmaking skills are able to produce a tourbillon. The tourbillon cage weighs less than a single gram!


Tritium was previously used as the luminous material for the dial and hands. Today it is no longer used as this material emits radioactivity. Instead, Super-LumiNova is used today.

Watch Manufacture

A watchmaker is known as a manufacture (a French term) when the company itself produces the majority of the watch components. The most famous mechanical watch “manufacture’s” are, amongst others, Patek Philippe, Jaeger LeCoultre, A. Lange & Söhne.


The balance is part of the escapement. The balance regulates the watch. There are various balance frequencies:

21.800 Hertz with manual winding

28.800 Hertz with automatic winding

36.000 Hertz with Zenith chronograph (El Primero).

The higher the frequency of the balance, the better its resistance is to environmental influences, for example, positions.

Recessed pushers

These pushers are placed within the casing and are used to set calendar dates including, for example, lunar phase, month, or day.


A waterproof watch is equipped with seals at the crystal (glass), bottom and tubes. Yet not every waterproof watch is just as waterproof as the next! Wristwatches carry a specific DIN standard (8310) for the level of waterproofing:

1. Protected for dust

2. Protected against water (water resistant) – Splashes of water

3. Waterproof up to 3at/30m – For example, a car wash etc.

4. Waterproof up to 5at/50m – Rain, swimming

5. Waterproof up to 10at/100m - Swimming

6. Waterproof up to 20at/200m – Snorkeling, diving without (scuba) gear

To dive with scuba gear one should wear a diving watch!

Alarm clock

The classical (mechanical) wristwatch with alarm function is the Jaeger LeCoultre Memovox. In this watch, the alarm is triggered by a specially integrated gong. With ‘simple’ wristwatches with an alarm clock the alarm hammer only strikes the casing.

Tension Spring

The tension spring provides the watch with its power. In automatic watches it is wound by the movement of the arm, and otherwise it is wound with the crown.