Wines from the Cinque Terre DOC must be made up of at least 40% Bosco and can contain a maximum of 40% Vermentino and/or Albarola and a maximum of 20% of "other authorized white grapes." As mentioned above, we just recently took a look at the Albarola grape, and we've taken a few indirect looks at the Vermentino grape (in the context of the Favorita and the Pigato grapes, which are genetically identical to Vermentino), which just leaves us the Bosco grape, about which there is apparently very little to say. The Oxford Companion to Wine's entry reads in full: "ordinary white grape of Liguria." Jancis Robinson's Guide to Wine Grapes adds little more, as that entry reads "very ordinary Ligurian that forms the basis of Cinqueterre and oxidizes easily." Nicolas Belfrage, in his Barolo to Valpolicella calls the grape "strange, but not so wonderful." Besides Cinque Terre, Bosco is permitted in only one other DOC region, the Val Polcevara just west of Genoa in central Liguria, where it is allowed to make up no more than 40% of the blend.