This specific detail is on a lot of shunga designs depiciting this theme and it is said this use of incense burning by courtesans was to drive away the smell of their Western clients. Dutch women were not allowed to live in Nagasaki but Japanese courtesans were permitted to enter the compounds. They are watched (by the viewer) through a window of a Nagasaki brothel. This might be the explanation behind why 50% of American men and women who are…