Identification guide
Markings, Hallmarks & Signatures
A guide to the categories of mark found on watches and clocks and where they typically sit. Every diagram here is a schematic drawn for this archive, illustrating shape and placement conventions in general — none is a facsimile of a specific real hallmark, assay punch or maker's mark, which vary by country, period and office and must be checked against an official assay/registry source.
Where marks appear
Typical placement on a case and movement
Case back placement zones
Maker signatures are usually the most prominent engraving; hallmarks (where applicable to the case metal) cluster in a dedicated band; case reference and serial numbers are typically smaller and separate from each other.
Schematic illustration only — not a reproduction of any real mark
Movement plate placement zones
A movement typically carries its own maker's mark, a jewel count, and a movement number distinct from any case number — see the Serial Number Research Centre for how these differ by manufacturer.
Schematic illustration only — not a reproduction of any real mark
Maker signatures & factory marks
Maker signatures and factory marks
Oval cartouche signature
Many maker signatures are engraved or stamped within an oval or rectangular cartouche on the dial, case back or movement bridge. The shape itself carries no meaning — only the name or logo inside it does.
Schematic illustration only — not a reproduction of any real mark
A maker's signature identifies who signed the piece for sale, which is not always the same company that manufactured the movement — this was especially common in the Swiss établissage trade and with retailer-signed American and British watches. A factory or ébauche mark is a separate, often much smaller, punch identifying the actual movement manufacturer, and it is frequently on an inner bridge or under a balance cock rather than anywhere visible without disassembly.
Never assume the signed name manufactured the movement without corroborating evidence; see the establissage note in the Serial Number Research Centre for how to separate the two.
National hallmark traditions
Swiss, British, French & American conventions
Shield-form assay mark (general schematic)
Many European assay systems use a shield or shield-like outline enclosing a fineness symbol or town mark. The exact shield shape, symbol and required combination of punches is jurisdiction- and period-specific and must be checked against that country's current or historical assay office reference, not inferred from this diagram.
Schematic illustration only — not a reproduction of any real mark
Letter-in-circle mark (general schematic)
A single letter within a circular or oval punch is a common general form for date letters (British assay practice) or responsibility/sponsor's marks. The letter, font and punch shape that indicate a specific year or office are assay-office-specific and change over time — consult the relevant assay office's published tables.
Schematic illustration only — not a reproduction of any real mark
Lozenge / diamond registration mark (general schematic)
Diamond-shaped registration marks were used in Britain (and elsewhere) to record a registered design; the coded content inside identified the registration date and parcel via a published key, not a simple sequential year.
Schematic illustration only — not a reproduction of any real mark
Summary by tradition
- Swiss: historically lighter statutory hallmarking than Britain for watch cases; look instead for maker's punches and, since the Swiss "Swiss made" and metal-control rules, specific control marks tied to Swiss law.
- British: compulsory assay hallmarking for gold/silver/platinum through UK assay offices (e.g. London, Birmingham, Sheffield, Edinburgh), each with its own town mark, plus a date letter and fineness mark.
- French: state-controlled poinçons (fineness marks) including maker's poinçon and official guarantee marks, distinct in form from British hallmarks.
- American: no compulsory national hallmarking system historically; reliance instead on maker-stamped fineness (e.g. "14K", "STERLING") and case-manufacturer trademarks, which carry a different, lower evidentiary weight than a statutory assay mark.
Precious-metal standards
Gold, silver & platinum fineness marking
Gold
Marked either as a karat figure (e.g. "14K", "18K") or a millesimal fineness (e.g. "750" for 18-karat, "585" for 14-karat) depending on country and period. Both systems describe the same underlying gold content, expressed differently.
Silver
"Sterling" or "925" denotes 92.5% silver; other national standards (e.g. .800 or .835 European silver) exist and are marked with the corresponding millesimal number, often alongside a statutory hallmark in countries that regulate silver.
Platinum
Typically marked "PLAT", "PT" or a millesimal fineness (e.g. "950"); platinum hallmarking was added later than gold/silver in several national systems, so its absence on an older piece is not automatically suspicious and should be checked against that country's regulatory history.
A fineness mark alone never verifies date or origin; combine it with any statutory hallmark and the case/maker's punches present. Never treat a fineness stamp alone as proof of authenticity — it can be faked, or applied to a plated case, and physical assay by a qualified assayer is the only conclusive test.
Import & assay marks
Import marks and assay-office control marks
Several countries require an additional import mark when precious-metal items made abroad are brought in for sale, distinct from the mark applied by the country of manufacture. An import mark does not tell you where the piece was originally made — only that it was legally imported into that marking jurisdiction — and it may sit alongside, rather than replace, the manufacturing country's own marks. Consult the relevant assay office's own published guide for the specific symbols and dates used, since these have changed over time and this page does not reproduce any specific office's mark set.
Patent, registration & serial marks
Patent numbers, registration marks and serial numbers
Patent numbers
A stamped "Pat. No." or "Brevet No." refers to a specific patent filing for a mechanism or design, not a date of manufacture by itself. Verify the number against the issuing patent office's historical index.
Research patent numbers →Registration marks
A registered-design mark (see the lozenge diagram above, or later plain "Rd. No." numbers) protects an ornamental design, not a mechanism, and is coded by national registry rather than being a simple date.
Serial numbers
The general term for a maker's own sequential (or randomised) identifier. Which component it is stamped on, and what published table (if any) exists, is manufacturer-specific.
Open the Serial Number Research Centre →Continue your research