Fundoshi is the traditional Japanese undergarment for adult males, made from a length of cotton.
Nowadays, the fundoshi is mainly used not as underwear but as festival (matsuri) clothing at Hadaka Matsuri or, sometimes, as swimwear.
There are several types of fundoshi, including rokushaku, kuroneko, mokko and etchū.
The rokushaku fundoshi is a length of cloth, the dimensions being one shaku (34 cm / 14 inches) wide and six shaku (2.3 m / 92 to 96 inches) long; roku is Japanese for six, hence roku-shaku. The fundoshi is often twisted to create a thong effect at the back.
Etchū fundoshi is also a length of cloth, however it has a strip of material at the waist to form a fastening or string. The dimensions are 14 inches width by about 40 inches length, and it is tied with the material strip in front of the body. Etchū fundoshi was the form of fundoshi most popular among Japanese adult males as underwear from early 1900s to the end of the World War II.