500 Đồng

The National Bank of Vietnam's 500 Đồng of 1970 was printed by Thomas De La Rue at a point when South Vietnam's currency was under sustained inflationary pressure — the piastre had been losing purchasing power steadily since the mid-1960s, partly as a consequence of the massive influx of U.S. military spending distorting the domestic economy. De La Rue had printed South Vietnamese notes since the early years of the republic, and their security printing standards were considerably tighter than what Saigon's own facilities could manage.

The watermark remains the sole listed security feature — modest for a high denomination by that period's standards.