Osaka-naniwa tinware Osaka naniwa suzuki
Tinware adorning gentle sheen
Warmth of art delivered by artisans
Osaka Naniwa Suzuuki (Osaka Naniwa Tinware) is made from a tin alloy and produced in an area centering on Osaka City in Osaka Prefecture. In the past, tin mined in Japan was used, but nowadays tin is imported mainly from Thailand and Indonesia.
The characteristic feature of Osaka Naniwa Tinware is the subtle differences between pieces even made by the same craftsman, because each pieces is completely handmade. Tin is a relatively soft metal and difficult to process by machine; therefore, most of the work is carried out by hand.
The tin is a very stable metal, and its high durability is much appreciated. It is said that tin mellows the taste of sake, resulting in the production of beautiful sake drinking sets.
Rather cleverly artisans discovered that by hand-engraving fine concave-convex patterns inside a beer mug, longer-lasting bubbles are generated, and that a rim of a certain thickness gives a smooth and pleasant feeling when drinking. Flower vases and other tube-shaped articles are turned on a lathe. The highly-accurate turning gives products good airtightness preventing moisture and oxidation; particularly ideal for tea caddies.
History of tinware production harks back to the Asuka Period, and some tin works are stored in Shoso-in Treasure Repository. Tin used to be a material valued like gold and silver, which was only allowed in limited settings such as the Imperial court for dinnerware and Buddhist altar fittings. A literature called Jinrin-kinmouzui states the existence of tinware craftsmen in Kyoto and other areas of the Kansai region in the early Edo Period.
The production of Osaka Naniwa Suzuki began in 1679, it was recorded in Naniwa-suzume that describes tinware production that took root in Kamigata (areas of Osaka) with better distribution functions by the middle of the Edo Period. In 1714, first Suzuya Hanbei that had studied under a tinware artisan in Kyoto established himself in Shinsaibashi, where a number of tinware manufacturers gathered and settled gaining acclaim as a renowned area of tinware production. Upon the start of World War II, many craftsmen were drafted and material procurement became difficult, resulting in a production crisis. As shaping of the postwar tinware industry, Osaka Naniwa Suzuki was recognized by the then Minister of International Trade and Industry Sadanori Nakayama as a traditional craft.
General Production Process
- 1. Raw materials
Osaka Naniwa Suzuki uses suzu (tin) which are mainly imported from Thailand, Malaysia and Indonesia in recent years because of a spate of closures of domestic tin mining since 1950. It sports over 97% of tin alloyed with 3% of lead.
- 2. Molding
Tin melts at low temperature of 230°C, expanding the options of heat source including city gas. Following melting blocks of tin in a pot, melted tin called Yu is poured into a cement, clay or metal mold with a ladle. Melted tin hardens quickly if the mold is at low temperature, which requires reheating the mold to proper temperature by repeatedly pouring melted tin in and out.
Tin is removed out of the mold without breaking the mold once it is solidified. The perfect timing to remove the mold is when tin starts solidification but just before shrinkage. The tin-lead eutectic point is 186°C, when crystallization starts taking place in metallic melted tin. This is a signal for removing from the mold, but it cannot be observed from the outside. Molded tin may lose shape if pulled out of the mold too soon, or it may be stuck to the mold if left too long and cooled too much. The mold may break if solid tin is forcefully pulled out. The right timing of removing molded tin is judged by the artisan’s experience. Any excess of tin formed around the edge is eliminated after tin is pulled out of the mold.
- 3. Cutting
Round shaped tin requires cutting and shaping with a turning lathe. Molding offers a standard thickness, 1.5 times to twice as much, because tin thickness cannot be reduced during molding. Only proficient skills make it possible to align the opening of a tea leaf can with the lid precisely. An additional process step is required for long slender objects including vases and objects composed of two molded tin parts. Molded into two separate pieces, tin is plated off inside and outside and welded together. Different kinds of planes are used for smoothing, shaping and finishing, along with traditional, natural sandpaper, Tokusa (scouring rush) and Mukunoha (leaves of the elm tree), for polishing
- 4. Intermediate process
This process is of attaching a handle or spout which is not shaped with a turning lathe. It involves cutting, bending, and patterning with hammer tone.
- 5. Patterning
Patterning is a process of painting a pattern or design on the surface of shaped tin. Immersed in a nitric acid solution, the rest of the surface with a pattern painted using Urushi lacquer and enamel corrodes, making it pearskin finished (unevenness). The following process steps are carried out in sequence allowing the pattern to appear clearly: checking the appearance of the pattern, washing the surface with water, applying black or vermilion Urushi lacquer and wiping off. Patterning is very delicate, causing the degree of corrosion to be susceptible to the seasons.
- 6. Final finish
With the Urushi-painted surface dried, tinware needs another polishing with a turning lathe, and an attachment such as a handle is connected.