Many Japanese martial arts feature an obi as part of their exercise outfit. Such an obi is often made of thick cotton and is about 5 cm wide. The martial arts obi are most often worn in the koma-musub
Obis for budō. The colours range from yellow to brown corresponding to judo kyū levels from 5th to 1st.
In some Japanese martial arts the obi is hidden underneath the hakama. Pictured is a kyūdōka.
In East Asian martial arts, the black belt is associated with expertise, but may indicate only competence, depending on the martial art. The use of colored belts is a relatively recent invention datin
Two aikido black belts training
Some martial art schools use embroidered bars to denote different levels of black belt rank, as shown on these taekwondo 1st, 2nd, and 3rd dan black belts.