Urushi: a natural plastic!
Urushi is a natural lacquer made from the sap of the Japanese lacquer (urushi) tree. The sap contains the resin “urushiol”, which polymerizes when exposed to moisture and air. It then transforms into a very hard and durable plastic-like substance; however, urushi is a natural plastic! The Japanese lacquer (urushi) tree is a member of the Anacardiaceae (sumac) family and is native to China, Korea, Japan, and the eastern Himalayas region. Urushi lacquer has been used as a paint, an adhesive, and even for protective purposes and in various other ways in Japan since the Jomon period (circa 14,000-300 BCE).
History
Since ancient times, urushi lacquer has been indispensable in the manufacture of agricultural tools and in construction, as the strongest natural adhesive substance available, in addition to its everyday use as a paint. During the Asuka period (538-710), when Buddhism was introduced from China, there was a surge in the demand for quality urushi lacquer for use in producing artistic Buddhist statues and at religious sites. Urushi lacquerware art advanced in a unique way in Japan during the Edo period (1603-1868). Items such as daily-use tools and swords evolved from a focus on practical functionality, such as durability and strength, to an emphasis on aesthetic value. Back then, local clans in many areas of Japan encouraged the manufacture of urushi lacquer and lacquerware. These traditional techniques of each region have been passed down through generations, and are still being practiced today. Currently, urushi lacquer is produced in the ten northern prefectures of Japan. Only 3% of urushi lacquer is produced domestically, and most of it is used in the restoration of shrines and temples. The remaining 97% of urushi lacquer is imported from China.
Harvesting urushi lacquer
It takes around ten years for an urushi tree to grow fully and be ready for sap collection. Meticulous care is required during that time, such as regular weeding, vine cutting, and protecting the tree from animals. It is no exaggeration to say that ensuring the healthy growth of urushi trees is what takes the majority of time and effort in making urushi lacquerware. Collecting the sap from urushi trees is done every year from June to October. Workers scratch the surface of the urushi tree trunk to collect the sap in stages every three-to-four days; the work is staggered like this to lessen the burden on the trees. Just like losing blood is for humans, collecting the sap from urushi trees is like taking away their life force. That’s why only 200 ml of sap can be collected from each urushi tree . Moreover, the sap quality, such as its transparency and viscosity, varies depending on the time it is collected. So the quality of the collected sap determines its use, ranging from undercoating for lower quality sap to finishing work for higher quality sap. Here is a quick guide to sap collection time, and the quality of urushi lacquer produced using it:Mid-June to mid-July | Hatsu-urushi (First urushi)Quick-drying urushi lacquer. Mid-July to Mid-September | Sakari-urushi (Blooming urushi)The finest quality urushi lacquer, with a beautiful glossy texture and transparency; it’s used for finishing work. Mid-September to October | Sue-urushi (Ending urushi)Urushi lacquer used for thickening the coating base. October-November | Ura-urushi (Backing urushi)High viscosity urushi lacquer used mainly as a coating base.
Features and Uses
When urushiol, the main component of urushi sap, oxidizes and hardens, it acquires excellent acid-, alkali-, and alcohol-resistant properties. Urushi lacquer is also highly durable with exceptional water resistance, heat insulation and antiseptic properties. So far, there hasn’t been any synthetic paint developed that is superior to urushi lacquer! Applying multiple layers of urushi lacquer improves its strength, while its aesthetic value is enhanced using various decorative techniques that have been developed over time. These include makie, the drawing of patterns on the surface using gold and silver, and raden, which is creating patterns using shell pieces. Urushi lacquer is also used to bond the broken ceramic pieces of items that are being repaired using the Japanese art form of kintsugi. As more chemical adhesives have been developed in recent years, the focus has shifted from the original function of urushi lacquer as an adhesive to its aesthetic value as an art form. Urushi lacquerware items for daily use, such as bowls, trays and jewellery boxes, are popular for their antibacterial properties. Urushi lacquer also prevents the growth of fungi and insects, so it is applied to the floors ceilings and other areas of buildings. A new variety of urushi lacquer has been developed recently, using a mixture of urethane and cashew lacquer; this new type of urushi lacquer is used to make more affordable urushi lacquerware. Simply Native stocks urushi lacquerware that uses both this new urushi lacquer and the traditional and authentic urushi lacquer. Please check our product page for a description of each urushi lacquerware product.