Identifying Japanese gold hallmarks and kanji marks on a belt buckle

A gold belt buckle stamped with a few kanji characters, perhaps inherited and with no paperwork, raises three separate questions: is it really gold, what purity is it, and who made it and when. The first two can be answered reliably with the right tests. The third often cannot be answered from the stamps alone, and the origin of a piece should not be assumed from the script on it. This guide explains how to read the common marks and how to get a trustworthy answer.

In this guide

Purity marks versus maker marks

A piece can carry several kinds of stamp, and they mean different things.

• Purity or material marks. Japanese gold is usually stamped in karats, with K18 being 18 karat, and K24 for pure gold.¹ Millesimal marks also appear: 750 is 75 per cent gold, equal to 18 karat, 585 is 14 karat and 999 is essentially pure.² A karat number is a maker's claim about the metal, not an official certificate.³
• Plating marks. Stamps such as GP (gold plated), GF (gold filled) and thickness codes mark items that are not solid gold. Check these before assuming that a gold-coloured stamp means solid gold.¹⁴
• Maker and component marks. Letters or characters such as "SN" or "NS" indicate a maker or supplier, not purity, and do not by themselves show that the piece is gold.¹
• Official hallmarks. These are discussed below.

The Japanese term 18金 means 18-karat gold, and 純金 means pure gold, so those characters on a piece are plain purity claims.

The Japan Mint hallmark

Japan has an official hallmarking system run by the Japan Mint. The Mint's role in certifying the fineness of precious metal ware (hallmarking) dates from the establishment of its Saitama branch for that purpose in 1929.⁵ Japanese appraisal and dealer pages describe the resulting stamp as a diamond-shaped mark combining a number for purity in parts per thousand with a mark resembling the Japanese flag, indicating a piece that passed the Mint's testing.³⁴ A "750" in such a stamp corresponds to 18 karat.³

Important limits:

• The system is voluntary, so many genuine Japanese pieces carry no Mint hallmark, and the absence of one is not evidence of fake or foreign origin.⁴
• A hallmark does not guarantee anything about the maker, the period or the rest of the object. A Japanese dealer cautions that even a hallmark does not guarantee 100 per cent authenticity and that full evaluation needs weight, colour and instrument testing.⁴
• Hallmarks should be struck cleanly, but the only dependable check is testing the metal. Marks can be faked.

What about kanji maker marks?

Kanji on gold can be a maker's mark, a shop name, a purity claim, an auspicious phrase or a mark from another country that uses the same characters. On a belt buckle, that ambiguity is real. In one Omega Forums thread about an inherited, handmade buckle of about 20 grams with two kanji stamps, members offered translations of the two marks and first discussed a Japanese origin, but later said the wording seemed more consistent with Chinese usage. The thread did not reach an identification and noted that specialist reference books rather than websites would be needed.⁶ That is a reasonable illustration of the limits.

For comparison, a Japanese source points out that China uses marks such as 足金 for high-purity gold, so a gold stamp in kanji does not by itself identify the country.⁴

What can be said, then, is limited. Unless a hallmark, maker registration or documentation ties the stamps to a known maker, the origin and age of the piece should be recorded as unknown. If you want to find out more:

1. Photograph each stamp under good light and with a macro lens, together with the whole buckle.
2. Note stamp positions, whether the stamps look struck or cast, the construction (hand-forged or cast), the hinge and tongue mechanism and any wear.
3. Ask for help in specialist collecting forums for Asian metalwork and Japanese-language communities, giving the photos and noting that you do not yet know the origin.
4. Consult a specialist in Japanese or Chinese metalwork or an auction house department for a considered opinion.

How to test gold without damaging it

• Weigh it and look at it. Weight and a consistent colour are a first filter. A buckle that feels too light for its size may be hollow or plated, but weight alone proves nothing.
• Avoid scratching and acid on a possible antique. Scratch and acid tests remove metal and can mar a piece that may have historic value. Acid also involves hazardous chemicals; leave it to a professional.
• Use a non-destructive test. X-ray fluorescence (XRF) identifies the elements present without damaging the item, and a benchtop analyser can report gold, silver and other metals in seconds.⁷ XRF reads near the surface, so ask a jeweller to test more than one spot and to check for plating or a filled core. Fineness can also be verified by destructive assay, which should be reserved for scrap.²
• A magnet can show a steel core under thin plating, but a non-magnetic result does not prove solid gold.

Getting an appraisal

Ask a reputable local jeweller, a gemmological laboratory or an auction house specialist. For a purity-only answer, XRF testing is quick. For the object itself (maker, period, collector interest), seek a specialist, and ask them to write down what they tested and what they could not determine. If you are in Japan, the Japan Mint offers hallmarking and fineness testing of precious metal ware.⁵ Get more than one opinion before selling a piece that may have value beyond its metal, and do not sell on the basis of a single verbal estimate. Check how any buyer calculates value: metal weight and purity are one thing, and collectible value is another.

Preparing photographs for a hallmark identification request

Take one photograph of the complete buckle before concentrating on the stamps. Then photograph each mark straight on and with light coming from two different directions. Include a ruler in a separate image for scale. Keep an unedited original; heavy sharpening or automatic contrast can turn wear marks into apparent characters.

If the script is difficult to read, ask for a transcription first and an attribution second. A correct character reading still needs to be connected to a maker, place or period. Describe the object as a buckle with unidentified marks until that connection is established.

A record to keep with the object

Searching beyond the phrase “Japanese gold hallmark”

Try K18 belt buckle hallmark, gold buckle kanji maker mark and a confirmed transcription of the stamp. Search a translated meaning only after checking the characters. This avoids building a chain of conclusions from an uncertain visual reading.

Purity and appraisal are separate answers

A metal test may answer what is present at the tested locations. It does not name a craftsman or establish an age. Ask an appraiser to distinguish measured results, supported attribution and unresolved questions in writing, particularly before repair, polishing or sale. Preserve packaging and old photographs even if they seem unrelated; they may help establish the object's history.

Sources and further reading

1. Japanese gold stamps, Otakaraya: Japanese buyer's explanation of K18, 750, plating marks and maker marks.
2. Fineness, Wikipedia: karat and millesimal fineness, and verification by assay or XRF.
3. Japanese versus international hallmarks, Satei Lab on note: appraiser's article; the Japan Mint mark and K18 versus certification.
4. Gold hallmarks in Japan and abroad, Kaitori Daikichi: Japanese dealer column; voluntary hallmark, plating stamps, 足金.
5. Japan Mint, Wikipedia: the Mint's hallmarking activity and the 1929 Saitama branch.
6. Anyone know something about Japanese gold hallmarks, Omega Forums: forum discussion of an unidentified buckle.
7. FAQs about testing jewelry with benchtop XRF analyzers, Evident: instrument maker's overview of XRF.