Die Proofs Selection. 1977, Felix Dzerzhinsky, Founder of Soviet Secret Police, die proof of 4k in indigo (issued in gray black), artist N. Cherkasov, engraver V. Smirnov, size 90x120mm, slight fold at top left corner far away from die, printed on wove paper without gum, NH, mostly VF and very rare, Est. $500-$600 (Image)

Die Proofs Selection. 1977, Soviet Icebreakers, 4k-20k, complete set of seven die proofs in indigo, black, brown, blue or violet, artist A. Axamit with group of engravers, each one with printer's markings at sides, approximate size 120x87-90mm, proof of 4k with two paper folds, 6k has tiny marginal thin, otherwise VF and extremely rare in complete set, Est. $2,500-$3,000 (Image)

Die Proofs Selection. 1980, Avicenna, Physician and Philosopher, sunken die stage proof of (4k) in black brown, artist S. Pomansky, engraver V. Smirnov, size 100x108mm, full OG, VLH, VF and very rare, Est. $500-$600 (Image)

Die Proofs Selection. 1980, definitive issue, Soviet Flag, die proof of 3k in bright red (issued color), artist A. Kalashnikov, size 88x119mm, printed on wove paper without gum, VF, Est. $500-$600 (Image)

Die Proofs Selection. 1981, Mstislav Keldysh, Mathematician, President of the Academy of Sciences, sunken die stage proof of 4k in brown (engraved color only), artist G. Komlev, size 95x107mm, full OG, NH, VF and very rare, Est. $500-$600 (Image)

Die Proofs Selection. 1981, Vitus Bering, Cartographer and Explorer, die proof of 4k in blue, artist I. Malukov, size 89x120mm, no gum as produced, NH, VF and very rare, Est. $500-$600 (Image)

Die Proofs Selection. 1981, Centenary of Welding, invented by Nikolai Bernardos, two sunken die stage proofs of 6k of black color only, one is complete engraved design, the other one has Bernardos' portrait only, first one with printer's markings and manuscript ''Correct letter ''B'' (on proof it is oblique at top left), sizes 115-120x100mm, printed on gummed paper with traces of hinging, VF and probably unique couple, Est. $1,000-$1,200 (Image)

Die Proofs Selection. 1982, Public Transportation in 19th and 20th Centuries, (4k)-(32k), complete set of six sunken die stage proofs (engraved part of the design), artist V. Karasev, each one with printer's markings at sides, approximate size 100x120mm, 6k with minor changes compare to issued stamp, printed on stamp gummed paper, traces of hinges, VF and extremely rare, Est. $3,000-$3,500 (Image)

Die Proofs Selection. 1982, Public Transportation in 19th and 20th Centuries, (4k)-(32k), complete set of six sunken die stage proofs, parts of engraved designs, artist V. Karasev, each one with printer's markings at sides, approximate size 100x120mm, two proofs with minor corrections, printed on stamp gummed paper, traces of hinges, VF and very rare, Est. $2,500-$3,000 (Image)

Die Proofs Selection. 1983, Aram Khachaturyan, Composer, die proof of 4k in violet brown (issued color), artist V. Koval, size 120x86mm, stamp ink soiling on reverse, no gum as produced, small hinge at left, VF and very rare, Est. $600- $800 (Image)

Die Proofs Selection. 1983, Muhammad ibn Musa al-Khwarizmi, Persian and Uzbek Mathematician, sunken die stage proof of (4k) in dark brown (issued stamp has engraved part of the design in red brown), artist A. Adashev, engraver A. Lukyanova, size 98x120mm, full OG, traces of hinges, VF and very rare, Est. $500-$600 (Image)

Die Proofs Selection. 1983, Ivan Fedorov, First Russian Book Publisher, die proof of 4k in gray (issued color), artist I. Malukov, size 83x108mm, no gum as produced, NH, VF and very rare, Est. $500-$600 (Image)