Metal processing technology arrived in Japan in the Yoyoi period. Since then the Japanese improved the techniques and created various products from the objects distant from daily life, such as ceremonial, religious implements, weapons, and Buddhist statues, to tools used in daily life, such as pots and cauldrons. The metal ware on display here was selected from the viewpoint of tools to be used in daily life. Two directions of metal manufacture are contrasted: the preservation of traditions and the coping with our contemporary lifestyle. I wish you to feel the future of the tradition of Japanese metal ware in the comparison of these two directions.
Iron
The history of metal casting is said to date back to around 4,000 years BC in Mesopotamia. Bronze, an alloy of copper and tin that is hard but has a low melting point, was the metal that opened up the way to metal vessels and implements. Progress led to the technology to produce higher temperatures and to work iron, enabling people to use iron utensils. Iron utensils performed very well as blades, and it can be imagined that in the early days the metal commanded a higher price than gold. The technology to cast metals apparently first reached Japan before the beginning of the Christian era, and in about the first century AD, advanced casting techniques were being used to produce bronze items such as bell-shaped vessels, mirrors, and swords. Mountain sand with silica as its main component was suitable for sand-casting, and this sand was used by packing it around a wooden or wax pattern to create a cavity of the desired shape. Molten metal was then poured into the cavity to produce the casting. Manufacturing techniques using sand-casting gradually improved until they were good enough to make Buddhist statues and temple bells. The technology to manufacture iron implements then reached the parts of Japan where iron sand can be found, and the tatara, a furnace that burned charcoal at high temperatures, enabled the production techniques that came to be used for the advanced blades needed for Japanese swords (nihontō). The Tohoku region still has many areas that retain knowledge of production techniques for iron implements using casting techniques that have been passed down over the centuries. The iron kettles exhibited here are still being manufactured in Iwate prefecture and Yamagata prefecture. The iron has the distinctive texture of a casting, and a rough “arare ”surface pattern said to be an attempt to increase the bottle’s surface area, which demonstrates the way that the new techniques are developed in the context of daily life.
Copper
The exhibits presented here are tea canisters and wire mesh utensils. Copper’s ability to be worked in fine detail and its resistance to corrosion have given it a firm place in the world of traditional Japanese craft, which developed in close proximity to food culture. Copper is easily worked, resistant to corrosion, conducts heat very well, and has good bactericidal properties. With these characteristics, it is used in many familiar applications, becoming an irreplaceable part of our everyday lives. Copper has a low melting point, enabling it to be melted just by burning charcoal, which leads to the view that either copper or bronze was the first metal to be used by humans. It is a very plastic metal, lending itself to deformation processes such as cold rolling and extrusion. It is also a ductile and malleable metal. Cut surfaces are an aesthetic delight, and alloys can be produced with a large variety of colors and engineering characteristics appropriate for a range of applications. Each of these characteristics is a distinctive feature of copper. When heated, copper has excellent forgeability, making it suitable for shaping into complex products. Moreover, the metal has outstanding heat conduction, and this leads to its use in high grade kitchenware. Copper cookware such as pans and frypans rapidly distribute the heat so that it is applied evenly to the food, giving such cookware an important role as professional kitchen implements that facilitate the fine adjustment of temperatures.
Tin
Tin is a metal that gives the impression of being as dignified as gold or silver. With a high level of purity, tin becomes very soft, and thin objects made of tin can be easily bent by hand. It can be shaped with a hammer, leaving hammer marks on the metal that enhance the fine and elegant appearance. Naturally, this process also makes the product more pleasing to the touch. The metal’s resistance to oxidation and strongly antimicrobial properties probably led to its reputation for keeping water fresh or enhancing the flavor of sake.
The exhibits here focus particularly on utensils that are bendable and on delicate, handmade drinking vessels. High purity tin has a bright silver color, and some tin sake cups have gold foil applied to the inner surface, creating a sake cup with an elegance that is very different from that of a ceramic cup. Sake servers with spout and handle include the chirori, used for warming the sake, and the tanpo, which also has a cedar lid to ensure that the sake stays warm.
Brass
Brass is an alloy of copper and zinc that strongly resists corrosion and is easy to machine. It has been used for a variety of household items since ancient times. Japan’s Shosoin Treasure House includes brass items imported from China in the Nara period, eighth century AD. Today, familiar applications for brass include its use in the five-yen coin, architectural fittings such as doorknobs, Buddhist altar accessories, and musical instruments. As a material, it feels soft, and although it shines brightly when new, it picks up a distinctive patina as its surface oxidizes through use, giving the impression that it is adapting to fit in with the people who use it and the places where it is used. The brass exhibits here include a lampshade and tray manufactured by sand-casting, an unadorned, slim and shapely bud vase called a “sorori”, and an “o-rin” altar bell. The lampshade and tray have delightfully textured surfaces produced by the sand used for casting.
Aluminium
Aluminium’s most outstanding characteristic is its lightness, only a third of the weight of steel or copper. It also has a low melting point but is strong, and can be machined with high precision for a wide range of applications ranging from paper-thin aluminium foil to the complex extrusions used for sashes and other construction materials. Its principal advantages are its lightness and suitability for detailed engineering applications.
The wall clock presented here is manufactured by sand-casting, using a high-precision process that produces a refined finish that belies the image of metal castings.
Aluminium cookware conducts heat better than steel, but its lightness is what makes it a popular choice for domestic kitchens.
The ice cream spoon symbolizes aluminium’s advantages of lightness and precision machining. Further machining to polish the surface enhances its ability to resist corrosion and keep microbes away.
Enamel
Enamelware is produced by coating the surfaces of metals such as iron, copper, and aluminium with a glaze of vitreous (glassy) material and firing them at a high temperature.
The coating provides a stable and hygienic surface that does not retain smells or affect the flavor of foods that it comes into contact with. Moreover, after cooking, the food can be left in the vessel and stored as is, with no need to transfer it to another container. However, because the surface is a vitreous material, it can crack when handled roughly, and may be damaged by sudden temperature changes. As enamel is a surface-coating technique, the resulting enamelware inherits the characteristics of the material coated. Consequently, enamel cookware fabricated by spraying the enamel onto a metal casting keeps the characteristics of the casting, so a heavy casting naturally results in a heavy pan. Enamel cookware manufactured by coating copper inherits the excellent heat conduction characteristics of copper cookware. And enamelware based on aluminium is consequently very light. The exhibits presented are an everyday pot, and food storage containers. With an enamel surface, there is none of the tension generated by a metal. Enamelware is somehow calming and reassuring.
Stainless steel
Today, iron is the base for a wide and diverse range of alloys and surface treatments that users select to suit a particular application. Stainless steel, which has the reputation of being resistant to rust and stains, is an alloy of iron produced by adding chrome or nickel. It gains the property of resistance to rust by means of a passivation film produced when contact with oxygen in the air results in a thin layer of oxide forming on the steel’s surface. The strength of iron can be seen in terms of a number of different aspects—including its resistance to rust, its hardness, toughness, and heat resistance—and the type of strength required differs according to the application. For blades, sharpness is required, but for jewelry and surgical instruments, there is a need for anti-allergenic characteristics.
The products exhibited here are pliers, radio pliers, nippers, and nail clippers, which are all hand-held tools. In addition to being rust-resistant and resistant to soiling, their use as tools requires them to be accurate and difficult to break, and their blades must be sharp. These are the product of long years of development and research in Sanjo, Niigata. Careful adjustment of the alloy composition and innovations in the annealing process have resulted in quality that Japan can be proud of as part of its contribution to the world.
