Junkin, in Japanese 純金, literally pure gold, is the Japanese trade term for 24-carat gold of nominal one thousand fineness. The term is used both informally and in marking conventions for retail jewellery, ingots and presentation pieces sold in the Japanese market.

Hallmark and marking practice

Japanese gold marking practice differs from European hallmarking in that there is no comprehensive state assay and no equivalent of the British Goldsmiths' Hall annual cycle. Instead, Japanese manufacturers and retailers self-mark gold with the K prefix followed by the carat number, as K24 for 24-carat, K22 for 22-carat, K18 for 18-carat, and so on. Items marked Junkin or 純金 are by definition K24 and are intended to be of one thousand parts per thousand fineness, although in practice the trade tolerates a fineness of 999.0 or higher as commercial Junkin and reserves 999.9 fine gold for investment-grade ingots.

Use cases

Junkin is used in Japan for several distinct purposes. Investment ingots and bars are sold by major Japanese refineries such as Tanaka Kikinzoku, Mitsubishi Materials and Sumitomo Metal Mining at one thousand fineness. Presentation pieces, including small votive plaques, leaf-form gifts, Buddhist devotional objects and traditional gift items, are commonly made in Junkin. Jewellery in Junkin is much less common because of the metal's softness, but it is used for some traditional and ceremonial pieces, particularly in the Kyoto craft tradition. Tea-ceremony objects, including chasen rests and incense containers, are sometimes produced in Junkin for high-end gift markets.

Quality assurance

Although there is no state assay, the Japan Jewellery Association and the Tokyo Commodity Exchange maintain trade standards for fineness marking, and reputable manufacturers participate in third-party verification by laboratories including the Central Gem Laboratory and the Gemological Association of All Japan. Investment-grade Junkin ingots usually carry a registered refiner's mark and a unique serial number.

Significance

For the international gold trade Junkin is the Japanese equivalent of the international 9999 fine gold standard, and Japan is one of the larger Asian markets for fine investment gold relative to its population. The term also appears as a marketing reference on Japanese jewellery sold to overseas markets, particularly through the Hawaiian and West Coast tourist trade, where Japanese-marked Junkin items are common in the second-hand market.