类型 (盘子) I - Sharp printing, outer line of color below bottom of stamp.
As a secret sign to recognize the original stamps from the fake ones, the engraver G. Masini placed one of the letters making up his surname in each value. These letters, in microscopic character, are found at the bottom near the outer line of the stamp and are not always visible. In the ½ grain there is a G, in the 1 grain an M, in the 2 grain an A, in the 5 grain an S, in the 10 grain an I (reported only in the 1st Table), in the 20 grain an N and in the 50 grain a I
