Horseman advancing right, holding a spear / Inscription in 4 lines "KNZ bVELIKIY IVAN PSK" ("Grand Duke Ivan PSK"). 14mmx11mm, 0.68 grams. Moscow mint. Griszin #73; Russian Wire Coins #73.
This is a full kopeck (not a denga), weighing 0.63 grams. The coin was minted in Moscow around 1540 when Ivan was still just a Grand Duke and not a Tsar.
The infamous Ivan "the Terrible" was the Grand Duke of Russia between 1533 and 1547. In 1547 he assumed the supreme title of "Tsar" ("Caesar") and ruled as such until his death in 1547.