10 Pesos Tesoro Nacional - Black type

Paraguay printed its own currency during the War of the Triple Alliance (1864–1870), one of the most catastrophic conflicts in South American history — the country lost an estimated half to two-thirds of its entire population by the war's end. The Tesoro Nacional notes were produced in Asunción under siege conditions, with the state press operating even as Brazilian and allied forces advanced. Local production meant no access to sophisticated intaglio equipment; the result was typeset letterpress printing, functional and blunt.

The watermark — unusual for a wartime domestic issue — suggests pre-war paper stock was still being drawn down rather than any deliberate security measure introduced during printing.