(1.) Secret mark - White dot at the inner edge of the 3rd triangle of the circle outline around numeral "1" moving clockwise from the bottom. This looks like a printing flaw but is actually a secret mark placed on the genuine stamps by the engraver.
(2.) Little tongue of the numeral "1" is thin, tapers, and curves slightly.
(3.) Six horizontal rows of pear shaped ovals in the background in the circle with small ends up.
(4.) "F" of Freimarke does not touch the line above it.
(5.) Exp: do. Ref: Earee.
(1.) Background lines form pear shaped objects with the small end up.
(2.) Little tongue of the numeral "1" slants slightly upward at the end.
(3.) Secret mark is present. (A small white dot in the third triangle to the left of 6:00 o'clock at the inner edge of the central circle.)
(1.) No secret mark.
(2.) Little tongue of the numeral "1" has "slipped" downwards, is not tapered, and does not curve slightly.
(3.) Ovals in the background of the circle are not pear shaped.
(4.) Exp: do. Ref: Earee.