An oiran was, back in the earlier days, a high class Japanese courtesan or prostitute. They tended to wear the most expensive clothing available and were trained to be high-quality entertainers on top of giving services to their clients, who were generally the upper crust of society at the time.

The obi of a kimono worn by an oiran is tied at the front rather than in back, see?

I'm only half-pleased with it, and as per usual the scanner hates greys. :(