Horseman advancing right, holding a spear, letters "K-BA" below / Inscription in 5 lines "TSAR I / VELIKIY/KNYAZ IB/AN VSEYA/RUSY" ("Tsar and Grand Duke Ivan of all Russia"). 13mmx10mm, 0.67 grams. Novgorod mint. Grishin #87; Russian Wire Coins #87.
This is a full kopeck (not a denga). The coin was minted in Novgorod in 1560's.