This study investigates the characteristics of the two major dialects of Japanese: Osaka and Tokyo dialects. We recorded the utterances of the speakers of both dialects, and analysed the differences that appear in the accentuation of the words at the phonetic-acoustic level. The Japanese words that are phonologically identical in both dialects were used as the analysis target. The results showed that the pitch patterns contained the dialect-dependent features of Osaka Japanese. Furthermore, these patterns could not be fully mimicked by speakers of Tokyo Japanese. These results show that there is a phonetics-phonology gap in the dialectal differences, and that we may exploit this gap for forensic purposes.