Lacquer on shakuhachi
Lacquering the bore can make shakuhachi play louder and with a more crisp tone color. Whether this is better than the sound of an unlacquered bore is often subjective, however, a clear advantage to a lacquered bore is that it hardly ever grows mold, and if it does it is 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 and a dryer vent brush. 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 in the second or third octaves than more coats of lacquer can perhaps balance it out.
Lacquer and cracks
Shakuhachi crack because of an imbalance of moisture loss or gain which is usually caused by changes in the level of humidity. Lacquering every single surface of a shakuhachi is perhaps the best way to prevent cracking because it will stop the bamboo from experiencing shifts in humidity. However, many shakuhachi are only lacquered on the inside. While this helps prevent cracks from any sudden introduction of moisture to the inside of the flute, it increases the chances that a shakuhachi will crack at rest. This is because lacquering only the inside of the bamboo creates an imbalance by making the inside impermeable while leaving the outside permeable. This causes an uneven loss or gain of moisture which in turn leads to cracking. Un-lacquered shakuhachi are more susceptible to cracking from the sudden introduction of any moisture, usually from the breath or from cleaning. In the end, fully-lacquered is the best option for longevity while it’s a toss-up between just lacquering the bore and no lacquered at all. 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 shakuhachi from the elements and is perhaps the best way to prevent cracks.
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.