A Hadaka Matsuri (裸祭り, 'Naked Festival') is a type of Japanese festival, or matsuri, in which participants wear a minimum amount of clothing; usually just a fundoshi loincloth, sometimes with a short happi coat, and rarely completely naked.

Naked festivals are held in dozens of places throughout Japan every year, usually in the summer or winter.

The most famous part of the festival is when the shin-otoko (神男) enter the stage and has to find a way back to the shrine, called naoiden.

During the night time ceremony, all the bad luck is transferred in a charcoal coloured giant mochi.

The black mochi is made with rice mixed with the ashes of the burned Omamori from last year.