Abstract: Information as to the location, date and shift of manufacture of roofing shingles is cut into an edge of the shingles as a coded sequence of slits. Preferably, the slit sequence is coded using a binary coding scheme, with a separate binary number group defining each of the shift, the month, the day and the year of manufacture, in addition to plant site identification information. Based on the easily-cut, binary-coded slit sequence, used in conjunction with the plant site identification information, a manufacturer can quickly isolate the time and place of a manufacturing defect. The method of providing a roofing shingle with a coded indication of the shingle's time of manufacture involves arranging a physically-ordered sequence of slit cutting knives, based on a sequence of binary digits, in which a slit cutting knife is provided in the physically-ordered sequence when a corresponding binary digit in the sequence of binary digits is a first value (e.