Rhythmic categories such as morae in Japanese or stress units in English play a role in the perception of spoken language. We examined this role in Japanese, since recent evidence suggests that morae may intervene as structural units in word recognition. First, we found that traditional puns more often substituted part of a mora than a whole mora. Second, when listeners reconstructed distorted words - e.g. panorama from panozema - responses were faster and more accurate when only a phoneme was distorted (panozama, panorema) than when a whole CV mora was distorted (panozema). Third, lexical decisions on the same nonwords were better predicted by duration and number of phonemes from nonword uniqueness point to word end than by number of morae. Our results indicate no role for morae in early spoken-word processing; we propose that rhythmic categories constrain not initial lexical activation but subsequent processes of speech segmentation and selection among word candidates.