The shinobi shōzoku(忍び装束) is a type of dark-coloured keikogi clothing, purportedly worn by practitioners of the Japanese martial art of ninjutsu. It is made up of split-toed tabi boots ("jika-tabi") and socks; special trousers with double-ties which fasten at the ankles, knees and waist; a jacket with overlapping lapels which is tucked into the trousers; and protective arm-and-hand sleeves. A mask and a hood seen in movies are not commonly used. An obi belt to indicate the wearer's level of kyu or dan grade may also be worn. The outfit is made of strong, dark-colored fabric, usually black cotton, fitted loosely to allow freedom of movement. The jacket may sometimes contain a pocket for hidden weapons.