One of the most striking aspects of conceptual integration (or ‘blending’) is that it seeks to unify an extremely broad variety of conceptual phenomena – from the most startling feats of imagination and invention to the most mundane instances of conceptual composition – and treats them all as the products of a single cognitive process (or closely related suite of processes). This article focuses on metaphoric blends, and assesses properties that distinguish them from other blends, and lend them their particular quality. In particular, the paper examines the nature of metaphoric counterpart connections, and especially the “ready-made” connections, i.e., entrenched metaphoric correspondences between concepts, that provide the basis for the real-time construction of metaphoric blends. The paper argues that primary metaphors constitute a distinctive class of counterpart connections and they require an explanation not found among blending theory's other technical apparatus. These patterns of metaphoric association cannot be explained by mechanisms such as analogy, nor by relations such as cause-effect or identity, which underlie other sorts of blends. Instead they derive from recurring correlations between particular types of mental experiences.