WATCH MOVEMENT MARKINGS — CALIBER NUMBERS, JEWEL COUNTS & ORIGIN STAMPS
The movement (or calibre) is the engine of a watch, and the markings engraved or printed on it reveal key information about its origin, complexity, and capabilities. Caliber numbers, jewel counts, and country-of-origin stamps can help identify when and where a movement was made, and what features it may offer.
Understanding Caliber Numbers
A caliber number is a manufacturer's internal designation for a specific movement design. For example, Seiko's 7S26 or ETA's 2824-2 are caliber numbers that identify the exact movement architecture, including its features, dimensions, and complications.
Caliber numbers are typically engraved or printed directly on the movement and can usually be seen through a transparent case back or by removing the case back. Some manufacturers also print the caliber number on the case back exterior or dial.
Jewel Count Markings
The jewel count (e.g., "21 JEWELS", "25J") refers to the number of synthetic ruby bearings used in the movement. These jewels reduce friction at critical pivot points, improving accuracy and longevity. A typical basic automatic movement often has 17 to 21 jewels, while more complex movements with additional complications may have 25 or more.
It's worth noting that a higher jewel count does not always indicate a better movement. Some manufacturers have historically added non-functional jewels to inflate the count for marketing purposes. The placement and function of the jewels matters more than the raw number.
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Country of Origin and Regulatory Markings
Movements often carry country-of-origin markings such as "SWISS MADE", "JAPAN MOVT", or "MIYOTA" (a Japanese movement manufacturer). These markings are regulated by trade laws — for example, the "Swiss Made" designation requires that at least 60% of the movement's value is Swiss, and final inspection occurs in Switzerland.
You may also find regulation markings, such as adjustment indicators or certification stamps. Chronometer-certified movements may carry "COSC" or "CHRONOMETER" markings, indicating they've passed accuracy tests by the Contrôle Officiel Suisse des Chronomètres.
Shock Protection Symbols
Many movements feature shock protection systems indicated by specific symbols or text. Common examples include "INCABLOC", "PARASHOCK", "DIASHOCK", or "DIAFIX". These systems protect the delicate balance staff pivots from damage due to impacts.
Related Markings
A manufacturer's identifier for the specific movement (mechanism) inside the watch. This number reveals the movement typ
Jewel Count MarkingA marking indicating the number of jewels (synthetic rubies) used as bearings in the movement. This number reflects move
Movement Country of OriginA marking indicating where the watch movement was manufactured, such as "Swiss" or "Japan." This identifies the movement
Regulation MarkingMarkings on or near the movement's regulator indicating adjustment positions for timing accuracy. These are used by watc
Shock Protection SymbolA marking indicating the movement incorporates a shock protection system for the balance wheel. Common systems include I
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Frequently asked questions
Where can I find the caliber number on my watch?
The caliber number is most commonly engraved or printed directly on the movement. If your watch has a transparent case back, you may be able to read it without opening the watch. Otherwise, it's often printed on the case back exterior or listed in the manufacturer's documentation.
What does the jewel count tell me about my watch?
The jewel count indicates how many synthetic ruby bearings are used to reduce friction in the movement. Most standard automatic watches have 17-25 jewels. While more jewels can indicate a more complex movement, the number alone doesn't determine quality — placement and function matter more.
What does 'JAPAN MOVT' mean on a watch?
The marking 'JAPAN MOVT' (or 'JAPAN MOVEMENT') indicates that the movement mechanism was manufactured in Japan. This is commonly seen on watches that use movements from Japanese manufacturers like Seiko (Epson), Miyota (Citizen), or Orient. The case and assembly may have occurred elsewhere.
Is a higher jewel count always better?
Not necessarily. While jewels reduce friction at pivot points, some manufacturers have added non-functional jewels to inflate counts for marketing purposes. A well-designed 21-jewel movement can outperform a poorly designed 25-jewel one. Focus on the caliber's reputation rather than jewel count alone.
What does COSC certification mean?
COSC (Contrôle Officiel Suisse des Chronomètres) is a Swiss organization that certifies watch movements for exceptional accuracy. A COSC-certified chronometer must perform within -4/+6 seconds per day across multiple positions and temperatures over a 15-day testing period.
Can I identify a fake watch by its movement markings?
Movement markings can provide clues, but they should not be relied upon as the sole indicator of authenticity. Counterfeiters sometimes replicate movement engravings. Professional watchmakers can examine the movement's finishing, architecture, and components to provide a more reliable assessment.
What is Incabloc?
Incabloc is a widely used shock protection system found in many Swiss mechanical watch movements. It uses a spring-loaded jewel setting that absorbs impacts, protecting the delicate balance staff pivots from breakage. The Incabloc symbol (often a lyre-shaped spring) is frequently visible on the movement.
How do I know if my watch movement is automatic or manual?
Automatic movements typically feature a rotor (a semicircular weight) visible through a transparent case back. They also commonly have markings like 'AUTOMATIC' or 'SELF-WINDING'. Manual movements lack a rotor and must be wound by turning the crown. The caliber number can also confirm the type.
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