Online Lecture 5
Explanation of the Dry-Lacquer Technique
1. Introduction

Lacquer Provides an Extremely Interesting Modeling Material.
The oldest trace of lacquer use that has been found to date is a lacquered bowl dating back approximately 7,000 years that was discovered at the Hemudu site at the mouth of the Chang Jiang (Yangtze) River in Zhejiang Province, China. It is amazing to think
that red lacquer should have been used 7,000 years ago.

The oldest lacquer artifact in Japan is a red-lacquered comb dating back 6,000 years that was discovered at the Torihama site in Fukui Prefecture, but in both cases, the techniques used are remarkably advanced, making it likely that although archeological evidence has yet to be discovered, lacquer culture existed long before this time.

Traces of objects created by molding a form of putty, comprising of lacquer mixed with earth (to create volume and prevent running), on a wood, branch or vine core have been discovered that date back to Japan's Jomon period (10,000 - 300 BC) when the comb was produced. Therefore, it can be said that dry-lacquer techniques already existed at this time. However, with the introduction of metal culture during the Yayoi period (300 BC - 250 AD) and the development of wood-carving techniques, dry-lacquer techniques temporarily disappeared.

They were not to appear again in Japan until the seventh century when they were used to create the dry-lacquer coffins, thought to have been used by Prince Shotoku and other members of the nobility, or the statues of the Shitenno (Four Deva Kings) at Taima-dera
Temple which date to the latter half of that century. From around this period, the hollow- core dry-lacquer technique became very popular and continued so until the mid-Heian period (794-1185 AD) when it died out. The reason given for the abandonment of wood core dry-lacquer sculpture in favor of wooden sculpture are that Japan is a country with an abundant supply of timber while lacquer was, even then, a valuable commodity and difficult to work with.

2. Lacquer

Before I move on to present an explanation of dry-lacquer techniques, I think it is necessary for me to offer a brief description of lacquer itself.
Lacquer Tree
(Toxicodendron vernicifluum or Rhus verniciflua)
The grooves cut into the trunk to collect the sap.
The Leaves and
Flowers of the Lacquer Tree
The main material used in the creation of dry-lacquer sculpture is lacquer which is obtained from the sap of the lacquer tree. This lacquer, which is one of the representative materials of traditional Japanese art, is produced by cutting grooves into the trunk of the deciduous lacquer tree, then collecting and refining the sap that oozes to the surface. A coating of lacquer provides a beautiful, durable surface that is also ecologically friendly.

A lacquer tree is either male or female, producing flowers and fruit. Vegetable wax can be collected from the fruit and at Joboji in Iwate Prefecture, a place famous for its lacquerware, a coffee substitute is also produced by roasting these fruit.
The lacquer sap is collected between the months of June and November, the amount of water in the sap and the quality of the lacquer varying according to when it is collected.
When the sap oozes to the surface it is a beautiful, milky-white color. When this white liquid is exposed to the air, oxidization and the reaction of an enzyme called laccase cause it to gradually turn black.
The optimum temperature/humidity to obtain hardest finish is between 20-30℃ / 70%-85% which means that the Japanese spring rainy season is ideal.
The reason why this should be is that during the rainy season, there are a lot of decay fungus spores in the air and the tree produces the sap to facilitate rapid repair of any damage it may sustain.
Fresh Lacquer Sap
Lacquer Sap
After the sap has been collected, it is then refined according to its intended application.
It is placed in a tub and stirred to thoroughly mix the raw lacquer, then it is heated to evaporate all the excess water. Both of these steps are carried out in order to give the lacquer more body and better gloss.
The finished result is a transparent lacquer that can be used to accentuate the grain in wood or have color added to use as a form of paint.
Mixing and Heating
If iron powder is added to the lacquer during the mixing and heating, it causes a chemical reaction that turns the lacquer black. This is known as black lacquer and is used in the finishing stages of lacquering. Depending on the historical period in which it was made, ink or ash was sometimes added to the lacquer instead of iron powder to make it black.
Both clear and black lacquer can contain oil or not, that containing oil can be finished with a brush and is known as nuritate, while that without oil is polished after drying and is known as roiro.
Black Lacquer and Clear Lacquer
* (The above photographs are all reproduced from the quarterly publication, 'Ginka', no. 105, 1996)
The uses of lacquer include the following:
   As Pigment
   As coating medium / paint and varnish
   As a glue
   As a modeling material
Hollow-core dry-lacquer sculpting is a technique that makes full use of lacquer as both a glue and modeling material. Lacquer is often considered difficult to work with due to the fact that it causes allergic reactions and takes a long time to dry but it is a versatile material and if you experiment with it, you will understand the fascination it holds.
3. Hollow-core Dry-lacquer Sculpting Process

I would now like to move on to explain the hollow-core dry-lacquer sculpting process, illustrated with photographs. The photographs used here were taken during the production of a model of a hollow-core dry-lacquer sculpture created by a first-year graduate student for the gallery talk, ヤThe Secret of Buddhist Statuaryユ, that was held at this laboratory and the Tokyo National Museum.
1. Producing a Wooden Core for the Statue

This is a small statue about 60 cm. tall so it only requires a simple core. In ancient times, before the ripsaw was invented, coniferous wood, etc. was split using a wedge then finished with a knife or yariganna (a simple form of plane). Planes with a stock also did not exist at this time so the base of the column would also be finished using a yariganna.
A rope is wrapped around the column to facilitate the adhesion of the clay.
Dry-lacquer sculptures can either have the central core removed or it can be left inside after the lacquer has been applied.

2. Application of the Clay as in Classical Statues

In this project, both rough and finishing clay have been used, but it is not known whether this was done in ancient times. However, as the clay has to be covered with cloth, it is considered unlikely that straw would
be left protruding from the clay.
Hemp cloth is glued to the clay figure using a mixture of flour and lacquer.
The cloth is pressed into the cavities using a spatula while the clay is still
soft, the overlapping of the cloth at this stage will provide strength to the statue. Sometimes glue, not lacquer, was applied to the cloth for the first layer.

3. After the cloth has been applied a hole is opened, generally in the rear or some other unobtrusive area, and the clay removed.

After removal, a new wooden support is inserted and fastened in place with nails. Circular boards are fixed in place inside the shoulders and hips to prevent shrinkage.
After the wooden core has been affixed, the cover of the hole is sewn back into place using hemp cord. In
the case of this project, splits have been opened left and right in order that the interior may be viewed.
The hands are made of wood with copper wire as a core for the fingers.

The Central Wooden Core
5. The modeling is carried out using kokuso, a putty made by adding wood powder or plant fibers to a mixture of flour and lacquer.
[Left] The shape is further refined using sabiurushi (a mixture of burnt clay [tonoko] and seshimeurushi [sap taken from the branch of the lacquer tree]). [Right]

The rahotsu (spiral curls of hair) are carved from wood and glued into place. The fingers are wrapped in cloth soaked in lacquer then detailed using kokuso.

6. Gold leaf is applied to the surface using lacquer then the finish is 'aged'.