Bolivia, Philip IV, 8-Reales, (16)51, Potosi, assayer O, 24.2 g., similar to preceding but · P · O ( · 8 · O ) · vertically and stamped with type U countermark on obverse (Cal. 1034 var.; CN. --; CT. 427 var.), king's name and date partially clear, fine, countermark unevenly struck and so only partially visible, but clearly identifiable, very rare