Urushi is lacquer. Everything else is attempt to mimic its appearance. Or has split of from "japanning" and become clear coat.

I have not researched Cashew, kashew very much. It was developed in the 1930's i believe as a safe alternative, and cheaper, and easier to use than urushi.

Like oil paint kashew dries / cures via evaporation; wheres urushi does not.
urushi cures from a chemical reaction with water vapor.