5000 Reis Bolama seal

Banco Nacional Ultramarino's Guinea series was a colonial banking exercise built on plate economy — the same Bradbury Wilkinson designs served multiple Portuguese territories with minimal modification, differentiated primarily by overprint or seal. The "Bolama seal" designation here refers to the administrative stamp identifying Bolama, then the capital of Portuguese Guinea, as the issuing branch. Bolama lost its capital status to Bissau in 1941, which lends these early issues a minor geographical footnote that later notes in the territory lack.

BW's intaglio work for colonial Portuguese issues of this period was consistently high quality, though that hardly distinguished the note in the hands of a population where coin remained the trusted medium.