Rare Russian 18k Definitive Issue

18k pair definitive issue. Image of Raritan Stamps.

At the beginning of the June unique imperforated 18k pair of the definitive issue was sold at Raritan Stamps auction for $8,000. The peculiarity of this pair was the absence of a chalk net on it. It was an extremely rare item because only a few pairs are known to exist.

The origin of the 18k imperforated stamp is not clear. Perhaps, this stamp with a vertical chalk network is a probe. And the same stamp without a chalk network - from accidentally imperforated sheets or from sheets of probes with a strong shifted chalk network. 

The stamp was sold in small quantities at philatelic stores in 1927. Known copies from one or two sheets. There are philatelic covers with the imperforated probe 18k, dated in spring and summer of 1928.

In modern catalogs, these stamps are placed in the category of probes.