Blood circle

Delimiting the blood circle for a knife

The blood circle, also known as a safety circle, is a term used by the Boy Scouts to describe the area within the radius of the arm and blade length combined, when using a pocket knife, knife or axe. This area can be envisioned as a sphere with a person and a sharp instrument at its center. Presumably, anyone within this radius is at risk of being wounded by an accidental slip of the blade. Therefore, it is desirable to keep other people outside of the circle at all times.

Delimiting the blood circle

The circle is found by holding the blade of the cutting instrument (never the handle) in the hand used for cutting, and slowly swinging the arm in a 360° arc. The far end of the handle marks the limits of the circle. Any person or thing within this circle is considered to be at risk of injury. While it is never a good idea to enter another person's blood circle, it is customarily the responsibility of the knife-holder to clear the circle, or to move cautiously (after closing their knife) if the circle cannot be cleared.

Controversy

While the term is in common use by members of the Boy Scouts of America it is not found in any official publications of the organization.