Adjectival participles have been classified by their syntactic and semantic functions in many languages. Among the semantic functions, it is proposed that "reversible/irreversible interpretation" of those forms have a distinctive property. Like English, German, Greek and Turkish, it is claimed that Japanese adjectival forms have reversible/irreversible distinction as well. This study aims to verify the reversible/irreversible interpretation of Japanese adjectival forms proposed by Morita (1988) and clarify the factors related to this interpretation based on some concrete examples. To verify Morita's (1988) claim, we analyzed Japanese adjectival forms based on some semantic diagnostics proposed in previous studies (Kratzer 2000, Embick 2004, Gürer 2014, Kira 2018). In contrast to previous proposals, our findings indicated that Japanese reversible/irreversible distinction behaves in the same way that Turkish does; reversible/irreversible interpretation is mainly related to the verb to which adjectival forms attach to and the modified noun. Our results obtained in this study are significant in that reversible/irreversible distinction of adjectival forms, which does not only occur in Turkish but also in Japanese, have a possibility to become indispensable semantic diagnostics for future contrastive researches.