Great Britain
George III Counterstamped 1/2 Dollar ND (ca 1797) VF30 NGC, S.3767, KM-. Oval countermark with portrait of king George III upon Spain, Madrid 4 Reales 1791. Counterstamp VF, host coin about VF. Far more difficult to find than the companion 8 Reales type.
Estimate: 400-500 USD