A characteristic, though not necessary, property of so-called pitch accent languages is the existence of unaccented words. Work on unaccentedness in Japanese has found a concentration of such words in very specific areas of the lexicon, defined in prosodic terms. While unaccentedness might be some kind of default, the prosodic rationale for the way it is distributed over the lexicon is far from clear. This article investigates the underlying structural reasons for the distribution and develops a formal Optimality Theory account, which involves two well-known constraints: R IGHTMOST and N ONFINALITY . The tension between the two, usually resolved by ranking (N ONFINALITY ≫ R IGHTMOST ), finds another surprising resolution in unaccentedness: no accent, no conflict. Besides providing a more detailed analysis of Japanese word accent, which takes into consideration other mitigating phonological and morphological factors, the article aims to gain an understanding of the similarities and differences between pitch accent and stress accent languages.