The Japanese art of Urushi is a tradition dating back 10,000 years. This natural lacquer is sourced from the caustic sap of the indigenous Urushi trees. The Urushi is applied by the hands of select Japanese artisans. Once the lacquer cures it hardens around the natural rosewood body changing its resonant frequency. All Koetsu Urushi models use silver cladded ultra-high purity copper coils. This process involves a silver sheath being slowly drawn over the copper. Many say the Urushi body Koetsus offer an even more exciting sonic signature compared to the standard Rosewood models.