1 Ducat - Willem I Countermark

The VOC applied countermarks to foreign gold ducats circulating in their Asian trading networks as a form of authentication — confirming the coin had passed through company hands and met acceptable fineness standards. By 1771, the VOC was already in serious financial decline, hemorrhaging capital through corruption, mismanagement, and the mounting costs of territorial administration in Java. The company would be dissolved entirely in 1799, its debts absorbed by the Batavian Republic.

The Willem I designation refers to the Dutch stadholder, though the undertype is the operative numismatic question here — the host coin's origin determines much of the piece's actual rarity and value.