The crafts dealt with in this chapter － ivory, kirikane (cut gold), cloisonne, glass, gemstones and ink stones － all have long traditions and histories.
Shippo, the Japanese term for cloisonne, literally means 'seven jewels' and refers to gold, silver, lapis lazuli, crystal, shako (giant clam), amber and agate.
The technique of firing glassy enamels onto gold, silver or copper bases dates back to the time of Ancient Egypt. Substantial developments took place in the Middle East during the Byzantine period, while fine examples of cloisonne were made in Western Europe during the Middle Ages. Cloisonne technology was introduced to Japan via China and Korea in the Nara Period (710-794). The earliest evidence of the craft is found in metal fittings excavated from tumuli (kofun) graves dating from the 6-7th century and also in the form of mirrors preserved in the Shosoin Treasury. The metal fittings of the Phoenix Hall of the Byodoin Temple in Uji are also famous. The second half of the 19th century saw the invention of new cloisonne techniques by Kaji Tsunekichi (1803-1883) of Owari Province (present day Aichi Prefecture) and the development of translucent enamels by Gottfried Wagner (1831-1892), a German chemist in the employ of the Japanese government. These led to the establishment of important cloisonne industries in Tokyo, Kyoto and Nagoya.
BODY AND ENAMELS
The bodies of cloisonne items may be made from copper, tando (an alloy of 90% copper and 10% zinc), silver or gold. Of these, copper is the easiest to process and thus the most frequently used. Its coefficient of expansion is such that the enamels adhere particularly well.
Bodies are usually made by hammering, the thickness of their walls being in the region of 0.5-0.7mm.
Enamels are made of powdered silica mixed with red lead and alkaline materials in ratios similar to those used in crystal glass. Differences in degrees of transparency and refractive index result in translucent, semi-translucent and opaque colours.
Enamels are also classified according to the materials used and the type of body, silver or copper for example, for which they are intended.
Due to improvements in technology, there are now several hundred different enamel colours available to the cloisonne artist. These cannot, however, be mixed like oil paints but have to be used separately. Colour, it may be said, is the life and soul of the art of cloisonne.
PRINCIPAL TECHNIQUES OF CLOISONNE
Yusen-shippo (cloisonne (with wires)) = The most common form of cloisonne, whose origins lie in China, whereby thin metal wires are fixed to the body in accordance with the design and the areas between them are filled with enamel. When parts of the enamel surface rise above the level of the metal wires, the term moriage-shippo (lit. 'raised cloisonne') is used.
Musen-shippo (wireless cloisonne) = There are two ways of making wireless cloisonne. The first involves the application of enamels to a body to which no wires have been fixed. The second involves the application of enamels to a body to which metal wires have been temporarily fixed followed by the removal of the wires prior to firing. This is a particularly demanding technique.
Dei-shippo = This term is used to describe the opaque, matt enamels of the sort made prior to the development of bright, translucent enamels. They are the ancestors of modern opaque white enamels and are suitable for the creation of works of a subdued character. Dei-shippowares were made in large numbers in the early to mid-Meiji period (1868-1912) and were exported in bulk to the West. They were made with synthetic glazes.
Totai-shippo = Cloisonne wares in which part of the body is cut away and filled with translucent or semi-translucent enamel in contrast to the opaque enamel of the rest of the piece. The resulting effect is similar to that of stained glass.
Shotai-shippo (plique-a-jour) = Cloisonne which, having been made with translucent or semi-translucent enamels in the standard yusen-shippo manner, is dipped in a bath of nitric acid. The metal body dissolves, leaving only the enamels and metal wires.
Blown glass can be mould-blown or free-blown. Among decorative techniques, the best known are cutting (kiriko), etching and engraving. The techniques of cut glass used on 19th century Edo-kiriko and Satsuma-kiriko have been passed over the generations and are still widely used today. Etching, engraving and sandblasting were introduced from the West in the modern period.
People are fascinated by the transparent and fragile beauty of glass. Evidence of the degree to which glass has been prized in Japan can be found in the form of the white glass bottles preserved in the Shosoin Treasury, the free-blown glass balls used on Buddhist sculptures of the Nara period (710-794), and the beads (tombo-dama) and glass fragments excavated from ancient archaeological sites.
Glass production began to develop into a modern industry and craft discipline following the introduction of European manufacturing methods and decorating techniques in the mid-19th century. Glass is made by adding agents such as soda and lime to silica and heating in a kiln to a temperature of over 1000℃. Colours are obtained by the addition of different metal oxides. The techniques of glass-making are broadly divided into forming and decorating methods, the combined uses of which give rise to a wide range of effects.
Chubuki (free-blowing) = A small amount of glass melt is picked up on the tip of a blowing rod and air is blown through to produce a round form that is then, while it is still hot and soft, modelled into shape with the aid of metal tools.
Katafuki (mould-blowing) = The glass melt picked up on the end of a blowing rod is blown into a mould made of plaster, clay, wood or metal. Today, wood and metal moulds are the most common.
Pate-de-verre = Paste made from ground glass mixed with a binder is put into a fire-resistant plaster mould and fired in an electric kiln. The glass melts to form a vessel in the shape of the mould.
Cutting (kiriko) = Parts of the glass are cut away by moving the object against a rotating cutting device such as a grinder. Rough cutting is followed by whetstone-grinding and polishing. Only straight lines, curved lines and a limited range of circular motifs can be created by this method. Edo-kiriko and Satsuma-kiriko are the best known varieties of Japanese cut glass.
Engraving = This technique has been in use in Japan since the early Showa period (1926-1989). The area of the glass to be engraved is coated with abrasive powder and then moved against a small rotating copper plate. Different effects are achieved by using different types of copper plate.
Sandblasting = Carborundum mixed with compressed air is blown directly onto the glass to create a smoked glass effect.
Etching = This involves the application of hydrofluoric acid to etch away parts of the surface of the glass. The technique was extensively used by Art Nouveau artists such as Emile Gallet and the Daums Brothers.
Kirikane has a long tradition that dates back to the Heian period (794-1185). Used principally in the decoration of Buddhist paintings and sculptures, it involves the application of multiple layers of extremely thin gold and silver foil to an underlying substrate. Kirikane flourished in particular during the middle to late Heian and Kamakura (1185-1336) periods, but declined from the middle of the Muromachi period (1336-1573) onwards. Its techniques were subsequently preserved only in the Higashi-Honganji and Nishi-Honganji Temples in Kyoto. Nowadays, kirikane has become an established craft, with artists making use of fine foils to create delicate but opulent designs in which geometric patterning is combined with straight and curved lines.
The gold and silver foil is prepared by being hammered out to a thickness of less than 1 micron (1/1000 mm). Being so thin, it tears and wrinkles very easily and has to be handled with extreme care. Tweezers and knives made of bamboo are used to cut the foil into fine lines, squares, rectangles or circles on a stand covered with buckskin. The designs thus created retain their distinctive beauty and lustre for generations.
Ivory has been used by man since earliest times, its density, hardness and sheen making it an ideal material for carving.
During the Nara period (710-794) ivory was employed in the making of bachiru (polychrome ivory) work footrules using ivory stained red, green and navy blue, marquetry using white and coloured ivory, and ivory sword-handles and sheaths. The Shosoin Treasury, for example, is famous for the red bachiru work footrules that have survived from this early period. During the Edo period (1615-1868) ivory was used in the making of netsuke, toggles used for hanging dress accessories from the sash worn with traditional Japanese clothing, and during the Meiji period (1868-1912) it was used in the creation of elaborately carved ornamental sculptures (okimono).
The techniques of bachiru work have their origins in Tang dynasty (618-906) China. Ivory whose surface has been stained red, green or blue is finely engraved so that motifs show through in white against a coloured ground. The staining technique has recently been rediscovered, allowing the revival of the tradition by artists working today.
The history of gemstone processing in East Asia has its origins in Zhou dynasty (1050-221 BC) China, where it was used in the making of burial accessories, and the tradition has continued up to the present day. Japan also has a long history of gemstone work dating back to early times, the techniques having been introduced to areas such as Izumo (present day Shimane Prefecture), which is rich in raw materials like agate, crystal and jasper. Numerous examples survive in the Shosoin Treasury. Gemstone work of this early period is found in the form of Buddhist artefacts and on dress accessories, musical instruments and mirrors. During the Heain period (794-1185), however, these traditions began to decline and by the Kamakura period (1185-1336) had been died out completely. There was then a revival in the form of gemstone polishing by hand when crystal ore was discovered near the foot of Mount Kongo in Yamanashi Prefecture at the end of the Edo period (1615-1868).
Information about the techniques used can be gleaned from works such as the Shokunin-zukushi-e (Illustrated Compendium of Artisanal Crafts). Increasing interest in the skills of gemstone processing during the Meiji period (1868-1912) stimulated the importation of various kinds of precious stone and the establishment of gemstone work as a recognised craft discipline. Today the area around Kofu in Yamanashi Prefecture produces more carved gemstones than anywhere else in the world.
Gemstones are broadly classified as either hardstones or softstones. The oldest examples of Japanese gemstone work are large hardstone beads from the Jomon period (10,500-300 BC), the materials most commonly used for beading being agate, jasper, crystal and amber. For carved work the favoured materials are jade, agate, white crystal, red crystal, green quartz, amethyst, tiger's eye, lapis lazuli, sodalite and malachite.
Once the material has been chosen and the design worked out, under-drawing is carried out on the surface of the stone. Work progresses gradually, the first step being to use carborundum to make small wedge-shaped cuts resembling a toothcomb along the lines of the under-drawing. The unwanted parts are then removed by grinding with carborundum and a rotating device fitted with a round iron tip (koma). Increasingly finer grades of carborundum are used as the shape takes form. Final polishing is carried out with chrome oxide and a rotating wooden tip.
Ink stones and ink sticks (sumi) have been unearthed in China from sites dating back to more than 2000 years ago. Since then Chinese ink stones have been made either from fired clay or so-called Tankei stone. Ink stones were introduced to Japan from China along with other aspects of continental culture. Ceramic ink stones fired in Sue ware (Sueki) kilns from the 5th century onwards are frequently found at archaeological sites. The true development of Japanese ink stones did not, however, occur until after the 12th century. The expansion of learning and literature in the 17th-18th century led to increased demand for ink stones, which in turn encouraged the development of new centres for ink stone production in various parts of the country. Amahata ink stones from Yamanashi Prefecture are especially fine and are as sought after as Chinese Tankei ink stones. Although ink stones are essentially utilitarian items used for writing, the high level of craftsmanship that goes into their making has meant that they have long been regarded as works of art.
Materials used for ink stones include clay slate and diabase tuff. The best known types are Akama-ishi (Shimonoseki, Yamaguchi Prefecture), Amahata-ishi (Kajikazawa-machi, Yamanashi Prefecture), Homei-seki(Horai-cho, Aichi Prefecture), Shiun-seki (Iwate Prefecture), Kohan-seki(Shiga Prefecture), Shakuoji-seki (Kyoto Prefecture), and Nachi-ishi (Mie Prefecture).
Ink stones are made largely by hand. The initial piece of stone is carved with chisels to make it flat and roughly shaped with an electric saw. Chisels with very hard blades of tungalloy are then pushed from the shoulder on wooden shafts to carve the ink stone into shape. Polishing is carried out with rough and fine whetstones, and in the final stage of the process the ink stone is covered with a thin film of wax or urushi lacquer applied by cloth. Ink stones may be square or round, or may utilise the natural form of the stone. They may also be embellished with various kinds of patterning.
Shosoin Treasures (ivory) = Examples of bachiru (polychrome ivory) work footrules preserved in the Shosoin Treasury on which designs have been finely engraved into red, green and blue surface-stained ivory.
Netsuke = Decorative toggles popularly used in the Edo period (1615-1868) for suspending dress accessories such as tiered medicine containers (inro) and tobacco pouches from the sashes worn with traditional Japanese dress. They are usually carved in the form of containers, plants, animals or human figures.
Butsuga = General term for Buddhist painting of all kinds, including wall paintings and books with silk or washi paper leaves.
Shako = Giant clams from the seas around Taiwan and Okinawa and one of the shippo (Seven Jewels) in Buddhist terminology. Shako was highly prized as a decorative material.
Tojitai-shippo = Cloisonne with a ceramic (as opposed to a normal metal) body.
Shosoin Treasures (cloisonne) = Ancient cloisonne work is very rare, but amongst the Shosoin Treasures is a twelve-lobed mirror made of silver whose reverse is richly decorated with cloisonne enamels.
Crystal glass = Glass of extremely high translucency containing very few bubbles obtained by the removal of iron from the raw materials used.
Hakururi = Faintly coloured white glass with a high silica content of the sort found alongside examples of blue glass and green glass in the Sh?s?in Treasury.
Art Nouveau = An anti-traditional artistic style that flourished in France and Belgium in the early 20th century that was characterised by the use of curvilinear designs and the incorporation of organic forms.
Kujaku-ishi = Malachite, a mineral containing copper carbonate and copper hydroxide whose natural patterning is reminiscent of peacock feathers, has been used for decorative purposes and as a pigment since early times.
Chinese ink stone materials = China is blessed with many varieties of stone suitable for the making of ink stones. These have always been much sought after in Japan as well as in China. The oldest and most famous variety is so-called Kemboku stone, but there is also Tankeistone, prized since the middle of the Tang dynasty (618-906), and Kyujo stone, admired since the late Tang and the following Five Dynasties period (906-960).