Suteteko is underpants with the long length under the knee, and it is usually worn by men. Unlike sarumata (short underpants) and momohiki (long underpants), suteteko is loose-fitting and doesn't stick to the skin. It is worn on underpants, under trousers.
In the period of the modern Japanese development since the Meiji period, it became a common in the whole country as underwear to be put under kimono or hakama (pleated loose-fitting trousers). It is usually white, made of plainly woven cotton cloth.
After the War, textile industry flourished in Japan, and for the very warm and humid Japanese climate, new materials and weave technique, such as yoryu-crepe and calico-weave, were introduced,
At present, in daily life, mainly the males past middle age wear it.
The name 'suteteko' originates from the story that around in 1880, during the first Sanyutei Enyu (in fact he was the third) was performing his 'suteteko dance', his underwear under kimono was being seen.
Originally suteteko is underwear, so it shouldn't be worn without any clothes on it both inside and outside. At festivals, for shouldering or pulling mikoshi (portable shrine), or dashi (float) or jiguruma (float), participants wear it as a substitute for momohiki (in this case it means worker's close-fitting trousers). At men's naked festivals, sometimes a few men, wearing it as a substitute for loincloth, are found.
These days, suteteko is likely to be avoided for its bad appearance, however, it works as underwear that protects the knee and the thigh, absorbs the sweat in summertime, makes the movements of bending and sitting smooth like slip and juban (underwear for kimono), and prevents trousers from being damaged.