Toothless perforation in the form of pinpricks, without a security mesh.
Such a stamp with a security mesh and localized perforation (“pinpricks”) is cataloged only in N. F. Mandrovskiy’s catalog No. 154a. Without the security mesh, it is not described anywhere.
In 1908, stamps of the Eighteenth definitive issue of the Russian Empire were released with a new design for denominations from 1 to 10 kopecks. The remaining stamps retained the previous design. A new paper was developed and used for these stamps: without a watermark, but with a special chalk rhomboid mesh. This was done to prevent counterfeiting.