The earliest recorded trace of urushi, the lacquer used in kintsugi and other Japanese crafts, dates back to the Jomon period in Japan, specifically around 5000 to 6000 BCE. Archaeological evidence shows that urushi was used to coat pottery and wooden objects.
I believe that the oldest known urushi-coated object was discovered at the Kakinoshima “B” site in Hakodate, Hokkaido, Japan, and could be as much as 9,000 years old.
Urushi lacquer is used as a traditional Japanese varnish made from the sap of the urushi tree (Toxicodendron vernicifluum), which is native to East Asia. The use of urushi is highly regarded for its durability, beauty and unique aesthetic qualities.
The raw sap of the urushi tree is toxic as it contains urushiol, a compound that can cause skin irritation (similar to poison ivy). However, once it is fully cured, it becomes non-toxic and food safe.
People interested in kintsugi often ask why urushi lacquer is so precious and expensive.
The process of harvesting urushi, the sap from the lacquer tree , is a skilled and labour-intensive task. The method has been developed and refined over centuries, particularly in Japan, to ensure the sustainable collection of this precious material.
Although used in kintsugi, urushi lacquer is more commonly used to finish all sorts of objects from boxes, to pens, to chopsticks and many other useful and decorative objects.
It has a deep, lustrous finish that can range from transparent to various colours such as black and red, depending on the pigments mixed with the sap.
The lacquer is very durable and when used in this way, can be polished to a mirror-like sheen. Its rich, glossy surface is prized in traditional Japanese art and crafts.
Reams could be written about the different qualities and types of urushi used in kintsugi and there is not enough time or space to scratch the surface here.
Most urushi today comes from Japan and China. There are many different grades/qualities for all the urushi lacquers mentioned here; I try to use the best I can source.
Ki urushi is raw urushi. Ki urushi is used to make up several of the elements used at different stages in kintsugi such as, mugi urushi [glue], sabi urushi [putty] and others. It has a beautiful deep brown colour when cured. To learn more about mugi urushi and sabi urushi see The Process page.
Kuro roiro urushi is black urushi – the colour produced by mixing in iron hydroxide with ki urushi. We use this a lot, once the layer of sabi urushi has cured, to build up a smooth foundation for the finishing coat. If you finish with silver, black will be the final layer of urushi before adding the metal powder.
Eurushi is red urushi – the colour is produced by mixing bengala with urushi. Again, this can be used to build up smooth layers after sabi urushi has been applied. Some use alternate eurushi and kuro roiro urushi. If you finish with gold or brass, red will be the final layer of urushi before adding the metal powder.
Kijiro urushi is a special urushi lacquer used specifically for wood – it gives a rich, amber, glossy coating – it takes many, many applications to create a beautiful finish.
The above are the urushi lacquers I use most often, but to do justice to the subject, you would need a dedicated website!
