Type O1: "The vertical line of the right numeral box retouched"
Type O2: "The vertical line of the right numeral box is unbroken and not retouched; the lower left frame function line unbroken"
Type O3: "The vertical line of the right numeral box is broken near the top and is weak at the middle; the lower left frame junction line is unbroken"
Type O4: "The lower left frame junction line is weak or broken above the top of the spandrel"
Type O5: "The lower left frame junction line is weak or broken both above and below the top of the spandrel"
Type O6: "The vertical line of the right numeral box and the lower left frame junction line are unbroken"
Type O7: "The vertical line of the right numeral box has a minute break about 0.4 mm from the top; the lower left frame junction line is unbroken"
