Metsubushi(目潰し?) (gantsubushi)- "eye closers", is the name for a variety of implements and techniques used by samurai police and other individuals to temporarily or permanently blind or disorient an opponent in feudal Japan.
One type of metsubushi was used by police for blowing powdered pepper or dust into the eyes of a suspect. It is described as being a lacquer or brass box with a wide mouthpiece for blowing on, and a hole or pipe on the other end for directing the powder into the eyes of the person being captured. One type of metsubushi was a powder made up of ashes, ground-up pepper, mud, flour, and dirt. For severe damage, it could also include fine-ground glass. It was kept in hollowed-out eggs (happō), bamboo tubes or other small containers. When confronted by an attacker, a person would throw the metsubushi in the attacker's eyes, blinding him, while the victim ran off or hid himself.