Urushi Lacquer on Shakuhachi
Lacquering the bore can make a shakuhachi play louder and with a more crisp tone color. Whether this is desirable is up to each individual though. A clear advantage of lacquer is that it hardly ever grows mold and if it does it’s easy to clean. Conversely, an un-lacquered natural bamboo bore can and will grow mold much more easily which requires periodic cleaning with distilled white vinegar. A few thin coats of lacquer is sufficient enough to helping to deter the growth of mold while having a minimal effect on the sound. However, if a flute feels slow or lacks clarity than more coats of lacquer can balance it out.
Lacquer and cracks
Many shakuhachi are lacquered on the inside. This helps prevent cracks from any sudden introduction of moisture to the inside of the flute, such as from the breath or from cleaning. It theoretically increases the chances that a shakuhachi will crack at rest. This is because lacquering only the inside of the bamboo creates an imbalance between the inside and outside which is un-lacquered. This causes an uneven exchange of moisture which may lead to cracks. Un-lacquered shakuhachi are more susceptible to cracking from the sudden introduction of moisture and of course they can still crack at rest as well. It would seem to be a tie or draw between the two except that lacquered bores are much easier to clean and do not usually grow mold. You can read more about cracks here.
About Japanese urushi lacquer
Urushi lacquer is made from the sap of the urushi tree. The sap contains “urushiol” which is an oily organic allergen found in plants of the family Anacardiaceae, especially Toxicodendron (e.g., poison oak, poison ivy, poison sumac). Cashew, mango, and pistachio are also in the same family and a lower quality lacquer is made from cashews. In sensitive individuals, urushiol can cause an allergic skin rash on contact known as “urushiol-induced contact dermatitis” AKA “poison-ivy rash”. The name comes from the Japanese word for the sap of Toxicodendron vernicifluum (漆 urushi). The oxidation and polymerization of urushiol in the tree’s sap when in the presence of moisture allows it to form a hard lacquer which is used to produce lacquerware.
The sap of the Japanese urushi trees contains the highest concentrations of urushiol thus forming the strongest and most adhesive urushi. Urushi made from Japanese urushi tree sap was so much more adhesive that the “maki-e” or “metal leafing” technique could only develop in Japan. The shakuhachi and its ancestors have been lacquered both inside and out with urushi lacquer for centuries. The Komuso monks often applied urushi lacquer to the entirety of their shakuhachi which served to protect their them from the elements.
Japanese urushi lacquer history
During the Edo period (1603-1867) the urushi tree was highly valued being proclaimed as one of the “shimoku” (four essential trees). There was an urushi-tax and people had to pay a part of the tax with urushi and urushi-wax which was made from urushi seeds and was used for the production of candles. There was also an urushi magistrate who collected the urushi-tax and took care of urushiware which belonged to temples and shrines.
There were special urushi craftsmen who traveled around the whole country to repair and maintain urushiware. Until 1959 the production of urushi-liquid was at its height and urushiware was still used daily. Urushi-liquid collectors earned a fortune with their work. However, from 1960 and onward cheaper urushi was imported from China and the employment of the urushi experts decreased.