This Souvenir Sheet has been printed on heavy paper without gum, 500 copies. At the bottom of it there is a text field: Left, in one line - "People's Commissariat of Communications of the USSR" and th.. Read more »e right, in two lines - the same text in French.
These were invitations to the first stamp exhibition of USSR. There are very small quantity of cancellated cards (with a red cancellation).
25 copies of the Souvenir Sheet in the upper part of the field was made typographic overprint in two lines: "the best participant of the Russian Society of Philatelists". These Souvenir Sheet are were sent to 25 people who made the greatest contribution to the development of Soviet philately - they all took part in the organization of the exhibition.
And 3 Souvenir Sheet of 25 were registered (with an additional manual overprint, indicating the position and name of guest). It was unique blocks.
1 block: for Chairman of the Presidium of the Moscow Society of Philatelists - E.M. Nurkas.
2 block: Chairman of the Presidium of the Leningrad Society philatelists (repressed and executed in late 1930s).
3 block: Head of the secret-operative management of the OGPU (repressed and executed in March 15, 1938).
That is (2) and (3) blocks lost for now.
Nurkas (1) was arrested and imprisoned in the Gulag. He presented his stamp collection to the prison' doctor. Doctor emigrated to the United States and took with him a collection. In 2008, its unique card was found and sold at auction for $776250.
USSR