This is a new type of incense box made of black persimmon wood. A beautiful grain pattern is visible.
The wood grain, reminiscent of suminagashi (ink marbling), flows from the lid to the body of the vessel. This kind of grain pattern appears because the wood is cut vertically during the manufacturing process. Cutting timber vertically requires lumber of a correspondingly large diameter. Finding timber from a persimmon tree that doesn't grow very large, and therefore suitable for vertical cutting, is extremely difficult, making it incredibly rare.
The price of black persimmon wood has continued to rise in recent years, and pieces with good grain patterns are becoming extremely difficult to obtain.
