Auction #93 Worldwide Air Post stamps and postal history, Zeppelin Flight items, philatelic rarities of the World

1913, Tercentenary of the Romanov Dynasty, Nicholas II, stage proof of 5r in reddish brown, unfinished design with complete engraved hatching and thickened corners of ''5 roubles'' but without hatching at the bottom of the oval, printed on wove paper, size 63x73mm, marked in pencil with ''13'' at top right, no gum as produced, VF and very rare, Est. $1,500-$2,000