All interpretations of the Portland Vase frieze to date have failed to see, much less explain, a crucial figural attribute in the frieze, one that proves to be both explicit and explicatory, and whose location and appearance secures the identification of not one but, indeed, three figures. Furthermore, the attribute lies at the heart of a distinct schema of figural grouping and arrangement which has also gone unheeded in previous treatments of the Portland Vase frieze. By dint of this previously (...) unknown attribute, one can straightforwardly read the opening scene of the frieze using the attributes therein provided, but the opening scene only. To complete the task, a second methodology–that which I laid out in Arion in 1992–is a categorical sine qua non. One can, as I have already shown, successfully navigate the entire frieze using the second methodology alone but, as so many others have shown, not contrariwise. These new findings–the attribute and figural plan–are clear proof that the artistic vision of the Portland Vase was purposefully executed in a two-part program. (shrink)