Those are called a collar clash mark. The are marks made on the edge of the die:
http://www.error-ref.com/?s=Die+cla...ollar+clash+
Second topic below. Note the die images. (Makes it easier to understand)
http://www.error-ref.com/?s=Die+cla...ollar+clash+
Second topic below. Note the die images. (Makes it easier to understand)






















