The wooden core is called kiji and is prepared by a specialist, the joiner. The type and thickness of the wood depends upon the object to be manufactured, which might be anything from a large piece of furniture or an entire temple building to a tiny incense box. Hinoki (Japanese cypress) is best suited for making boxes, including inro, as it does not warp or split. On the other hand hinoki was not usually used for such objects as netsuke because it is soft and tends to wear down. Most sword sheaths were made from honoki (Magnolia hypoleuca), a light wood; carved figures from himekomatsu (a species of pine), which does not split; cups and bowls from sakura (cherry), which is suitable for lathing; and other woods such as keyaki (zelkova) for their ornamental grain. Ornamental woods were either left natural or covered with transparent lacquers to bring out their beautiful color or grain (see "Transparent Lacquer," page 133). Occasionally only parts of such woods were lacquered or they were used for encrustations as practiced by Ritsuo. The wood of the camphor laurel is not suitable for lacquering because its camphor content acts on the lacquer. Woods to be lacquered were very well seasoned, some inro cores being hung up to dry for as long as three years before being lacquered.
The lacquered boxes (including inro) invariably have almost airtight snugly fitting parts, such as a lid or fitted tiers, or boxes enclosed within a parent box. The wooden core was so carefully prepared as to account for the thickness of the subsequent lacquer to be applied and still permit accurate coadaptation of the component parts of the object. And even then, after centuries of use and exposure to varying climates and temperatures, the boxes remain uncracked, unwarped, and perfectly fitting. Such was the extreme care and accuracy involved in the preparation of the wooden core.
The prepared wooden core was then primed and covered with numerous layers of lacquer by a special class of lacquerers called the nurimono-shi or nuri-ya, and finally the decorative and pictorial work was done by the more highly esteemed lacquer painters, or makie-shi. There was even further specialization of lacquerers, such as mother-of-pearl inlayers (aogai-shi) and even sword-sheath lacquerers (saya-shi). Mother-of-pearl itself was processed and prepared by special craftsmen. Frequently the design itself was done by a noted painter or was copied from a famous painting. Metal artists often combined their talents with those of the lacquerer and supplemented the work with metal encrustations. Metal inro were made by metal artists, and at other times lacquer was applied to a metallic base by the lacquer artist. The combining of talents among specialized Japanese artisans was not uncommon. Many famous painters, such as Korin and Zeshin, were also adept with the handicrafts. The handicrafts were not looked down upon as in China but were even practiced among the patrons of the arts along with painting, poetry, and calligraphy.
Honji: Priming the Core
Having outlined the process in the preparation of the wooden core and the production and use of the various basic lacquers, we are now in a position to understand how the various layers of lacquer are specifically applied to the basic wood. "Real basis" (honji) is the term used to denote the best black lacquer on wood. It should be again noted that the "basis" is done by the nurimono-shi and is merely preparatory for the lacquer painter, who then takes over to ornament the prepared lacquer base. The same "basis" is used on a lacquer foundation for colored or gold lacquer work. Similarly the same lacquer foundation is used even in raised lacquer work, although less commonly raised lacquer (takamakie) may be done on a natural wood base. In general after the lacquer base is applied the design is brought out by repeated dustings of metallic and colored powders associated with repeated applications of lacquer, drying, and polishing. In other cases the design is accomplished by superimposing layers of colored lacquer. Lastly the design may be brought out by inlaying or deeply encrusting various precarved designs made of gold, silver, mother-of-pearl, ivory, pottery, etc.
The steps used in honji consists roughly of the following. The wood is primed by adding a layer of seshime-urushi and then put in the damp press. Then the channels and joints are covered by means of a spatula with a mixture of seshime-urushi, chopped hemp, and rice starch, and the piece is again placed in the press. This layer is now rubbed down, and a layer of sabi is applied. After more time in the press the piece is rubbed down again. Then it is covered with hempen cloth (nuno) to prevent the wood from cracking and the joints from springing. Following this, several layers of mixtures of lacquer and clay are applied, followed by drying in the damp press each time and polishing each time after the drying process. The true lacquer stages now occur, and the lacquers are applied with a brush of human hair.
First the middle-coat lacquer is applied and then multiple layers of ro-urushi (black lacquer), followed by more and more careful polishing with powdered charcoal. The object is finally polished with a mixture of burnt Inari clay reduced to impalpable fine powder, and calcined deerhorn (tsuno-ko) is applied with cotton cloth touched with oil. The final coats are of seshime-urushi followed by drying and polishing with powdered deer's-horn ashes applied with the finger.
Up to sixty separate steps may be used in applying the basic lacquer layers on the wooden core. The minimal time used for just the damp press is twenty-two days, and sometimes thorough drying of one lacquer layer may take up to one month. A well-prepared lacquer base prevents warping, seals in the wooden resin, and does not allow the slight undulations or irregularities of the wood to show through.
Materials and Techniques of Ornamentation
After the honji is completed the lacquer painter commences his work. This consists essentially in transferring a prepared design over the prepared lacquer base and then filling it in according to the method he has chosen. At this point it should be stressed that to the lacquer artist the background is just as essential as the design itself. While in many cases the design is set off on a completely plain black or other colored lacquer background, more often than not the background is enhanced by dusting with various metallic powders and flakes. This technique is extremely important and is called nashiji, or pear ground. This technique is also used on the risers and on the inside of the inro cases as well as the insides and bottoms of the majority of lacquer boxes.
The design itself is usually done as follows: after the groundwork is completed the design is drawn on one side of the specially prepared paper with brush and ink. Then, using a fine brush (neji-fude) composed of the hair from the back of ship rats, the design is traced on the opposite side of the paper using moist (heated) lacquer. The finished design is then rubbed off onto the lacquered surface using a whalebone spatula. The lines are subsequently dusted with metallic powders and lacquer (ro-se-urushi). The entire design is now built up to the desired height or effect by repeated dustings using various types and sizes of brushes and dusting tubes (tsutsu) covered with fine gauze mesh. Repeated layers of lacquer followed by drying and repeated grinding down and polishing are also necessary. Similarly, colored lacquer may be superimposed in the same way. By using alternate layers of dustings and coats of lacquer, the design is gradually built up. In this way the artist is actually working in a three-dimensional medium even though the entire thickness of the design through the repeated rubbings may only be 2-3 mm. thick. Similarly, the design may be ultimately constructed as a completely flat surface and still maintain the three-dimensional effect by means of slight shadings in tones and the varying depths in the lacquer in which the dustings are done. It should also be noted that the colors themselves are altered according to the depth in which they are placed in the amber-colored lacquer layers. All of these factors have to be taken into account by the lacquer artist, who must be able to visualize step by step in advance the ultimate complete work, as any error in judgment cannot; be rectified by removal or erasure. The additional processes involved in the various lacquer techniques will be described separately.
In metallic dusting the following technical points should be noted: 1) deer's-hair brushes (menso) are used for spreading on thick lacquer preparations; 2) kebo, or horsehair brushes, of different sizes are used for applying gold dust;