In the Saru Dialect of Ainu, gliding of high vowel occurs at intervocalic positions. This description, however, is only partially true; consider ikoiomap. This peculiar distribution can be explained by regarding the gliding process as a result of (rightward) accent shifting. From the behavior of preconsonantal high vowels where leftward accent shifting is observed, we condude that they can be associated with a single requirement: to avoid having bare high vowels bear word accent, these two being extremely weak in prominence.