The Asian art and design collection of the Powerhouse Museum holds many fine examples of metal craft, including a significant collection of decorated Japanese tsuba (sword guards), as well as kozuka knife sheaths and handles, which use an alloy of copper and gold named shakudo.
This neckpiece also uses shakudo, as well as shibuichi (a copper-silver alloy), copper and sterling silver. It was made by Won Ho Chong in Adelaide, South Australia in 1981 and acquired in 1987 – making this the first Korean-Australian object in the collection.
Won Ho Chong was born on 28 October 1934 in Busan, South Korea, during Japanese occupation. Chong initially studied literature at university, although interest led him to traditional metal craft and design during the early 1960s in Seoul. In 1964 Chong started his own jewellery design studio, and in the following years he received awards at international craft and design competitions, such as in Japan and the USA. In 1967 he undertook an artist’s residency at the Yamada Reiko studio in Tokyo. Chong migrated to Australia in 1970 and in 1976 he studied Japanese metal craft under Master Satsuo Ando, among others, after receiving an Australia Council grant. From 1978-1981 Chong lectured at the South Australian College of Advanced Education, and it was in 1981 that he made this neckpiece.
Chong’s work is influenced both by traditional Korean and Japanese materials, techniques and craftsmanship, particularly the patination of different alloys to create a range of colours. The dark brown to black metal seen in the neckpiece is an alloy of copper and gold, named shakudo in Japanese or odong in Korean. It is also referred to by many other names, including ‘red copper’, ‘black gold’, and ‘crow’s gold’, the latter term due to the similarity of the classic blue-black colour to crow’s feathers. However, with different ratios of gold to copper, a range of colours can be achieved through patination. The blue-black colour is a result of 3-5% gold, brown to black colours are a product of 0.25-3% gold, and ‘purple gold’ has a gold content of over 10% (Oguchi 1983: 125 and O’Dubhghaill & Jones 2009: 290).
The silver-grey colour seen on the neckpiece is an alloy of copper and silver called shibuichi in Japanese, and is also known as misty or hazy silver. Shibuichi, or ‘a quarter’, is so named as the silver conventionally amounts to 25% of the alloy’s composition. Just as with shakudo/odong, there are colour variations in shibuichi, such as a light variant that contains a high amount of silver, and a dark variant that contains copper, silver and gold (Oguchi 1983: 125 and O’Dubhghaill & Jones 2009: 291).
Briefly, the traditional process of creating these alloys involves melting the copper in a carbon crucible, and adding the desired quantity of gold and/or silver. The alloy is then poured into a mould in a hot water bath, which slows down the cooling process and increases the workability of the ingot. It is then hammered or pressed into a sheet or plate and annealed. Surface finishing is vital to create the desired colours – first the piece is polished using stone and charcoal, then cleaned with sodium bicarbonate, dipped in a colouring solution made of the juice of white radish, and finally immersed into a boiling colour solution, where the colouration of the alloys take place (Oguchi 1983: 125-129 and O’Dubhghaill & Jones 2009: 291-293).
You can see this object and many more in Spirit of jang-in: treasures of Korean metal craft, but hurry as the exhibition closes this Sunday 12th February!
Alysha Buss, Assistant Curator for Spirit of jang-in: treasures of Korean metal craft
O’Dubhghaill, Coilin and Jones, A. Hywel, 2009, ‘Japanese irogane alloys and patination – a study of production and application’, in Proceedings of the twenty-third Santa Fe symposium on jewellery manufacturing technology, Albuquerque, New Mexico, May 2009, Met-Chem Research, pp 289-324.
Oguchi, Hachiro, 1983, ‘Japanese Shakudo: Its history, properties and production from gold-containing alloys’, Gold Bulletin 16 (4):125-132