150 Guaraníes Otto von Bismarck

Paraguay's 1974 commemorative program was an ambitious series of silver issues produced largely for the export collector market rather than domestic circulation, a common revenue strategy among smaller nations during the 1970s bullion coin boom. Bismarck's inclusion in a Paraguayan series is less arbitrary than it appears — German immigration to Paraguay was substantial in the late 19th century, and several agricultural colonies founded by German settlers still existed when these coins were struck.

The .999 fineness is unusually pure for a struck coin of this period; most sovereign silver issues of the era used .900 or .925.