Abstract: A method and apparatus for preparing container board having a corrugated medium and at least one liner formed thereon for folding which comprises a tool for displacing in a non-destructive manner the corrugated medium and the liner in a portion of the board to form a curved indentation therein. The device includes a separate tool for forming a line of weakness in the liner along the curved indentation portion of the board. This arrangement increases the dimensional accuracy of the container board by substantially eliminating the occurrences of “false” score lines or rolling scores.