South Africa officially requires "one blank visa page", but the interpretation of this is sometimes that "one blank page" constitutes two blank pages facing each other. Like most interpretations of immigration policy in South Africa, it varies by the luck of the draw, the phase of the moon and the breakfast menu in the staff cafeteria.

Note that this requirement holds true at the time of entry or transit through South Africa, and not at the time of departure from point of origin. I have known passengers who had the blank pages when they checked in, but then picked up an exit departure stamp on the blank page as they left the country and were then denied entry to South Africa. Also, the requirement holds true even if one is just transiting through South Africa and not entering - there is an immigration checkpoint for transit passengers that checks to ensure that there is a blank page (although if you don't have one, they tend to berate you and let you proceed with your transit rather than deport you).