Karakane (唐金) is the Japanese name for a category of decorative bronze alloys used in metalwork from at least the medieval period onward, particularly for cast Buddhist sculpture, temple bells, sword fittings (tsuba and related furniture), kanzashi hairpins and household ornament. The name literally translates as Tang (Chinese) metal, reflecting the Asian-continental origin of the bronze-casting tradition that the Japanese workshops inherited and refined.

Composition

Karakane is not a single fixed alloy but a family of copper-tin compositions, typically with copper around 80-85 percent, tin 4-8 percent, and minor additions of lead, zinc, antimony and trace elements that the makers manipulated to achieve specific colour and surface behaviour. Some recipes include small amounts of arsenic. The alloy is distinct from the related Japanese decorative metals shakudō (a copper-gold alloy producing a deep blue-black patina) and shibuichi (a copper-silver alloy producing greys and pale browns) — karakane is harder, takes a different patination, and was used principally for cast rather than wrought work.

Surface and patination

The characteristic appearance of karakane is a controlled brown-black to greenish-black patina developed through traditional rokushō (verdigris) treatments and prolonged handling. The patina is not a simple oxide layer but a carefully cultivated surface achieved through immersion in solutions of copper acetate, plum vinegar and other reagents, and stabilised through repeated heating, brushing and waxing cycles. The Japanese metal-finishing tradition treats the patina as an integral part of the object rather than a coincidental tarnish, and karakane patinas are graded for evenness, depth and tonal warmth.

Use in jewellery and ornament

In Edo-period jewellery and personal ornament, karakane appears in cast kanzashi hairpins, ojime beads (cord-tighteners on inrō), netsuke fittings and the smaller categories of personal metal ornament. Sword fittings represent the most studied register of karakane work, where named master smiths produced tsuba in the alloy as part of the broader vocabulary of Japanese decorative metals. The material continues in production for traditional craft use today and is recognised in the Japanese Designated Traditional Crafts framework.