Tayū (太夫) are the highest class of traditional courtesan in Japan. Though technically the highest class of oiran, a general term for the highest-ranking courtesans, tayū were distinguished historically from other oiran due to their intensive training from a young age in numerous traditional artforms, and the fact that they did not engage in sex work, unlike courtesans below their rank. Tayū were known for their training in Japanese tea ceremony, kōdō, ikebana, Japanese calligraphy, poetry, dance, singing, and the playing of traditional instruments, such as the koto. There are currently only 4 tayūs left in Japan. Aoi Tayū is the youngest amongst them all and the most popular.