Japanese Urushi is a sap drawn from a member of the sumac plant family, Anacardiaceae, which is called Urushi no ki in Japanese. Botanically this tree was formerly called Rhus vernicifera, but now is universally known as Rhus verniciflua.

The Urushi tree can grow to about 20 metres in height and the tree trunk can reach about 60-80 cm in diameter.

The trees used for tapping are planted in hilly or mountainous regions in various parts of Japan. The ground in which the trees are planted, and the kind of light they are subjected to, will influence the amount and quality of sap that the trees produce. To maintain a consistently high quality Urushi, the Urushi kaki can only tap a tree once a day, and then only in dry weather. The tree must be at least 10 years old and have a diameter of not less than 15 cm. The quantity of Urushi sap extracted per year from a single tree is only about 200 gr. Depends from the number of trees the final quantity of Urushi sap extracted. The harvest of the sap is organized from May until the end of November.