A folding knife, including a handle, with at least two parts connected to form a cavity therebetween, and a blade having a sharpened edge and a tang. The blade is rotatable between an open position and a closed position. The blade defines a first plane inside the cavity. The tang includes a step protrusion and a rounded protrusion. A stop pin restricts movement of the blade in an opening direction. The folding knife also includes a locking member rotatable from a first position, allowing the blade to rotate, to a second position blocking rotation of the blade by engaging one of the tang's protrusions. The engagement of the locking member with the step protrusion of the tang locks the blade in its open position, and the engagement of the locking member with the rounded protrusion of the tang locks the blade in its closed position.