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can be a lustrous purple to violet black, or a shade of purple (some shades are described as "like dark grapes"). Variations include shi-kin or kurasaki-kin, "purple gold", and u-kin, "cormorant gold," or "karasu-kin." In earlier times, there were perhaps fifteen different grades of shakudo. A pseudo-shakudo with no gold content was also produced at least once by the
Japanese Imperial Mint.
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middle of the Edo period, and published more generally, in
Japanese, in the early 20th century. Some simple recipes have been circulated, and some analysis of treated surfaces done in an attempt to understand the topic further, with considerable but still partial success. This process, an instance of soft-metal patination, known as niiro(-eko), or nikomi-chakushoku, and involving
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especially suitable for precious metal inlay work, but also browns, greens and even shades of blue-green. A variation with added gold is known as kuro shibuichi, and another is obore shirogane, "white metal with the colour of the veiled moon." There are also related compounds, such as sambogin and hojigin.
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an alloy of copper and gold, usually with 3-6% gold, but sometimes as low as 1% and as high as 10%, or higher. Tin is also sometimes also added, among other metals. In raw form, shakudo looks very like plain but slightly darkened copper, but depending on the patination process used, the final colour
27:
patination processes, traditionally used in sword-making, catches for sliding doors, and luxury highlights on larger objects, and in modern times, in jewellery. The alloys contain two to five metals. Some scholars believe that methods similar to those involved in irogane production may also have been
318:
Merano, Italy, 2016: Giumlia-Mair, "Technology
Transfer from Ancient Egypt to the Far East?", p. 1, "The materials discussed ... are artificially patinated copper-based alloys containing small amounts of precious metals such as gold and silver ... treated in aqueous solutions, so as to achieve
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an alloy of copper and silver, with the silver percentage usually between 15% and 40%, but varying as widely as 2% to 60%. The name means one quarter, a reference to one common formula. The raw alloy is of gun-metal grey or very pale bronze colour, while final colours include a wide range of greys,
356:
Tokyo, Japan, Tokyo
National University of Fine Arts and Music, 1983: Hachiro Oguchi, "Japanese Shakudo": "shakudo was utilised in various works of art, but found special application in the ornamentation of swords and their accessories, especially sword guards (tsuba), in metal catches (hikite) of
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The chemical colouring of the surface is the key to irogane metals, and the details of the processes, and especially the compositions of the materials used to bathe the metals, are passed on within
Japanese craft circles, and not widely documented, though some information was written down from the
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Irogane, or iro-gane, simply means "coloured metals". The same kanji character (金) is sometimes used for metal ("kane" or "gane"), gold ("kin") and silver ("gin"), and aside from the name irogane itself, these are elements of some of the irogane metal names. Others involve a combination of name
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Notably, the traditional patination methods affect each metal differently, and have little or no effect on silver and gold elements, allowing for interesting effects when an object comprising multiple metals is patinated in one go to produce multiple final colours. Other effects are created by
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Raw copper with natural impurities, including yamagane, and highly refined copper (akagane, motogane) have been known from early times, and the alloys can be traced back between 300 and 900 years, or possibly as much as 1200. Shakudo, for example, may be referenced back to at least the
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Many of the patination processes involve boiling the metal in the modifying solution, and the final colour can depend on the duration of the boiling period, which may range from minutes to hours. Suaka, for example, may advance from a light brown after 2–4 hours, to orange-brown after
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Tokyo, Japan, Tokyo
National University of Fine Arts and Music, 1983: Hachiro Oguchi, "Japanese Shakudo": "shakudo finds mention ... Japanese swords of the Edo period ... the sword owned by a military commander of Genji (Nasuno-Yoichi ... in the 12th century) was ornamented with
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12th century. Shibuichi has a history of 550–750 years, with samples known from the 1630s. Due to the precious metal content, shakudo and shibuichi were always used sparingly, for small fittings on weapons, doors, small containers, or furniture.
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various surface colors. ... some artificially patinated alloys in different colors ... similar to other modern
Japanese alloys ... were identified on Western objects dating to Roman times" – also referencing Craddock (1982), etc.
285:., eds., p. 133-136: Murakami et al, "Characterization of the black surface layer on a copper alloy coloured by traditional Japanese surface treatment" – "Irogane is the general term for the alloys coloured ..."
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Tokyo, Japan, Tokyo
National University of Fine Arts and Music, 1983: Hachiro Oguchi, "Japanese Shakudo", p. 125: "They were successful ... in colouring the surfaces of copper and copper alloys by chemical
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Sammelband anlässlich der
Fachtagung "Metallrestaurierung – Metallkonservierung" der Universität für Angewandte Kunst (Wien 2007): Miklin-Kniefacz, Silvia "Shakudo und Shibuichi" – "Farbige Metalle in Japan"
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Oxford, Butterworth-Heinemannm 1993: La Niece and
Craddock, eds, Metal Plating and Patination: cultural, technical and historical developments – Chap. 7, Murakami, Ryu, "Japanese Traditional Alloys"
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London, UK, 1988: International Institute for Conservation of Historic and Artistic Works, Studies in Conservation – The Conservation of Far Eastern Art (Kyoto Congress 1988 Preprints), Mills
103:(ni-kuromi-do), mentioned in earlier accounts, and sometimes described as a substitute for shakudo, and sometimes used as a component in making further alloys instead of raw copper
170:, has a history of at least 600 years but given references to at least one irogane metal, shakudo, go back 900 or more years, some similar process must have a like history.
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London, 1915: The Transactions of the Japan Society, vol. XIII: "Metals and Metal-working of Old Japan" as presented by Prof. Wm. Gowland, A.R.S.M., F.R.C, F.I.C., F.S.A.
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The colouring and finishing of irogane surfaces generally involves polishing and cleaning, and chemical patination, and might include some final waxing or other treatment.
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refined copper, often with a naturally-occurring small percentage of zinc or lead, which patination leaves somewhere between light orange and dark red
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that is fitted between the grip and the blade of the swords carried by samurai and the shĹŤgun, and the banning of ceremonial sword-wearing under the
21:(色金 "coloured metals") is the term for a set of Japanese metals – forms of copper (with natural impurities), and copper alloys – treated in
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Vienna, Bohlau Verlag, 2009: Griesser-Stermscheg & Krist, eds., Metallkonservierung, Metallrestaurierung: Geschichte, Methode, Praxis
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New Haven, CT, USA: The American Journal of Science and Arts, Series 2, Vol. 42, eds. Sillman and Dana,
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elements from component metals and colours, for example, and one a reference to alloy composition proportions.
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Tokyo, Japan, Tokyo National University of Fine Arts and Music, 1983: Hachiro Oguchi, "Japanese Shakudo"
149:" (a mix including some arsenic and / or antimony) to copper ore to make a base for production alloys.
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used in ancient Egypt and the Roman world, as well as China (wu tan) and Tibet (dzne-ksim).
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a mix of copper and arsenic, which some sources believe might have been equivalent to
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cutting through layers of patination to let underlying surfaces show through partly.
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a brass-like mix of copper, zinc and lead, usually 75–84% copper, and just 1–5% lead
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is raw copper, often containing some of one or more of tin, lead, silver and arsenic
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a bronze-like mix of copper, lead and tin, usually 77–93% copper, and 2–8% tin
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sliding doors...and in the decoration of metal boxes and other items"
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an alloy of copper, zinc, tin and lead, final colour yellow to brown
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had a material impact on production of irogane metals.
40:The single most common historical usage was on the
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255:"Tsuba – Art of the Japanese Sword – Glossary"
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174:6 hours, to red towards 10 hours.
405:Terminology (glossary) of swords – Yamagane
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69:The better known irogane metals include:
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76:or Shaku-do (literally "red copper")
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112:Yamagane, "mountain metal"
407:accessed 31 March 2018
143:Imperial Japanese Mint
193:Corinthian bronze
50:Meiji Restoration
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106:Akagane or Suaka
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86:or Shibu-ichi
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263:. Retrieved
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96:or Kuromi-do
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188:Mokume-gane
44:known as a
295:treatment"
265:2018-03-23
224:References
213:Panchaloha
208:Orichalcum
161:Patination
197:hepatizon
153:Finishing
84:Shibuichi
56:Etymology
417:Category
329:shakudo"
203:Electrum
182:See also
130:Karakane
101:nigurome
94:Kuromido
423:Irogane
218:Tumbaga
168:rokushĹŤ
124:Shinchu
118:Sentoku
74:Shakudo
32:History
18:Irogane
147:speiss
65:Nature
393:et al
283:et al
46:tsuba
42:guard
24:niiro
195:and
419::
384:^
362:^
334:^
300:^
274:^
268:.
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