1 Sol

The Banco de Tacna operated in one of the most disputed territories in South American history. Tacna was ceded to Chile after the War of the Pacific (1879–1884) and remained under Chilean administration until 1929, when it was finally returned to Peru following the Treaty of Lima. A bank issuing notes denominated in Peruvian soles while the city itself was governed by Chile makes this a genuinely unusual piece of monetary geography — the institution was Peruvian in identity, Chilean in jurisdiction.

Pick lists this as a very scarce issue, and given the bank's constrained operating environment, that scarcity is unsurprising.