GOENNE | What is Urushi? | Urushi Japanese lacquer and Kintsugi Supplies

Urushi is very precious to the Japanese. Antiquity discovered in Japan dated to over 9000 years ago. Japanese' use and application technique of this tree sap has reached its height that none other countries could match.

URUSHI Japanese Lacquer

The Gift from Nature

20th century industrialization and technological advancement has brought us abundant new materials. Most of which are synthetically engineered in lab and mass-produced in factories, using artificial material and chemicals. 21st century is the era when we started to see the impact that modernization has brought: pollution, mass depletion of resources, climate change, toxic-intake by human and animal etc...

Revisiting the ancient intelligence of Urushi lacquer cultivation and usage, we realized there is a lot this magical material has been providing. It is no doubt THE gift from mother nature.

What is Urushi?

urushi lacquer, Japan urushi, traditional kintsugi, Japan-grown urushi

Urushi (Japanese lacquer) is a natural tree sap from the urushi tree. Before the age of Super-Glue and epoxy, people has been using this organic material as a strong adhesive and coating material. When in its raw state, urushi lacquer is toxic to touch, the natural enzyme causes allergic reaction on the skin for most people. Howvever, after natural polymerization process, this material stabilizes and becomes water-repellant and extremely durable with anti-bacterial and deodorizing properties. The longer a lacquerware has been used, the more rich the luster finish would become.

100% all-natural. It is a magical gift from nature.

Uses of Japanese Lacquer

In Japan, lacquer is commonly used as adhesive and finish material for utensils, furnitures and architectural works. Doctrines from as early as 14th century, recorded urushi lacquer as herbal medicine for both internal and external use. In rural towns of Japan where urushi are cultivated, the plant is also served as local delicacy. Ask the urushi foresters and they would recommend "urushi tempura"! Japan is world-renowned for its lacquerware. All families use lacquerware for food serving, and it is common for schools, restaurants and hospitals to serve meals in lacquerware due to its hygienic properties and durability.

Properties of Japanese Lacquer

When in its raw state, urushi tree sap is volatile. The enzyme actively oxidates and ferments.

It's main ingredient URUSHIOL (also found in poison oak) is known to give people allergic reaction if in contact with skin. However, after natural polymerization (hardening), it stabilizes to become a solid and extremely durable material.

The ideal condition for polymerization is 25-30˚C at 70-80% humidity. High humidity speeds up the "hardening" of liquid lacquer. So "drying" is not the right concept when using lacquer. For centuries, Japanese urushi refiners have perfected their skills in calibrating the urushiol-to-water ratio and manipulating the enzymes too create a wide variety of raw urushi products suitable for different applications.

Japanese' mastery in urushi (from cultivating, tapping technique, refining methods to artisanal applications) have gained world-wide recognition to be of top quality.

Durability

Completely cured lacquer surface becomes water-repellent. It also resists acids, alkali, alcohol. It remains unaffected by highly corrosive substance. It is like the ancient-version of powder-coating but without the chemicals.

Anti-bacterial

Scientific studies has been conducted in Japan and found that urushi-lacquered surface effectively deters the growth of some major food-poisoning bacteria and one type of virus (salmonella, MRSA, E-coli, and COVID-19's SARS-coV-2 †).* As a result, urushi-lacquered food-serving wares such as bowls, bento boxes and chopsticks remains popular in Japan. Urushi research and studies have been conducted in Japan extensively, however data largely remains as reference within the country. With the growing demand in all-natural material and popularity in Japanese lacquer craft, we believe there will be more interests and scientific study on this material at a global level in the near future.

FOOD-SAFE? FOOD-GRADE?

Food-safe and Food-Grade standards from North America and EU countries are set up to test and qualify artificial and chemical materials for food-contact use (e.g. plastic, stainless steel, epoxy, chemical coating etc..). Japanese Urushi lacquer, uniquely as an all-natural material, has not been examined under such standards. However, it has been used as a finish material for dining ware and serving utensils for many thousands of years in Japan.

*Reference: Lab Report from Urushi Revitalization Association (test conducted by JNLA, Japan National Laboratory Accreditation system on natural urushi lacquer supplied by Minowa)

† lab test result: SARS-coV-2 virus applied on a non-porous urushi lacquered surface, after 24 hours in controled environment, the virus count was reduced by 99.9%

Natural Deodorization

As urushi deters bacterial growth, it also act as a deodorant. In recent years, companies in Japan has been incorporating urushi into products such as fabric, socks and in-soles.

Luster & Finishes

As a hardwearing material, urushi can take chiseling, sanding and polishing. Japanese lacquer craftsmen have perfected their techniques in creating a wide variety of delicate texture and decorative finishes for lacquerware. Through the hands of Japanese artisans, its unique beauty represents Japanese aesthetics like no other material does. This longer a well-crafted lacquer bowl is used, the more beautiful the surface becomes.

FAQ on Urushi-labeled products in the market

The most frequent question from overseas audience on kintsugi and japanese lacquer is whether specific urushi-branded product is a natural material and food-safe. In our past workshops, students brought in kintsugi kits they purchased or received from other instructors labeled as urushi without knowing what they are actually using. As kintsugi craft becomes a world-wide popular hobby, we started to see abundant kintsugi kits and products saturating the market. Capitalizing on the trend and growing profits, there are more and more merchandize packaged under the label of "Urushi" "New Urushi" "Shin Urushi". There is no regulation on using the word urushi in product naming, as a result, this confuses a lot of craft consumers especially from outside of Japan.

If you decide to learn and practice genuine traditional kintsugi craft, it would be wise to do research and understand what natural urushi is, read product labels and ask sellers a few additional questions about the product.

Rule of thumb is, natural urushi lacquer for use in traditional kintsugi and lacquer crafts is derived from urushi trees (classification: Toxicodendron vernicifluum) grown in Japan or China and some SE Asian countries.

Cashew oil-lacquer and many other urushi-branded lacquer are synthetic paint products produced in factory by chemicals to replicate the composition and behavior of natural urushi. If your intention is to use natural urushi for any reason (e.g. natural material, food-safety, respecting authenticity of a traditional craft etc...), you should read the label or ask the maker/supplier. Having said that, there are also good reasons why cashew lacquer and synthetic lacquer products are manufactured, such as hobby model-making, commercial and industrial applications including furniture, automobile, architecture components.

Urushi Rash & Allergy

Last but not least, it is important to learn how to handle urushi lacquer properly to avoid direct skin contact.. The urushiol content in urushi is what makes it durable, glossy and "food-safe". However, it is also the same content (when in wet state) that gives most people bad skin allergy like poison ivy. Once this element comes in contact with your skin and enters your body, it travels, so it doesn't mean only the area that comes in contact will have allergic reaction. The rash could appear anywhere, usually outer and inner elbow, palm, thighs etc... And touching or scratching it will make it spread. There is only temporary relief of swollen redness, itchiness, blistering until urushiol is completely out of your system, which could be 1-2 weeks.

Even artisans who handle urushi everyday, including urushi cultivators, have to prevent skin contact as much as possible, there is no immunity. Urushi foresters have to wear full protective gears even in the midst of hot and humid summer to minimize direct skin contact. Everyone has their own "remedy", hydro-cortisone cream would typically be recommended by pharmacists but usually does little to relieve. My personal best remedy is to run the skin under cold water, or put ice pack over infected area for quick and immediate relieve, the swellness and ichiness immediately subside until it flairs up again in the next episode.

Wear protective covering gear all the time while working with raw / wet urushi. Coat your arm and palm with a layer of lotion before working would also help to prevent quick absorption of urushi onto skin. In case you notice urushi touches your skin, wipe it quickly with oil. (soap and water won't do it). Follow by alcohol.

Note that completely cured (polymerized, hardened) urushi becomes very stable and non-toxic. It is when its in wet and raw state that you have too be extrememly cautious while handling.