This paper argues that Feature Inheritance of Chomsky (2008) is what is behind Nominative-Genitive Conversion (NGC), a Case alternation phenomenon observed in adnominal clauses in Japanese. Assuming that (i) adnominal clauses in Japanese are TPs (Murasugi 1991) and (ii) D assigns genitive Case whereas T assigns nominative Case (Miyagawa 1993), the author advances the hypothesis that D transfers its Case feature to T. This D-T association hypothesis allows us to capture some of the fundamental properties of NGC when combined with the idea that Feature Inheritance is optional (Ouali 2006; also Miyagawa 2017). It is also argued that the D-T association hypothesis can be extended to the more familiar C-T association when we look at Hichiku Japanese, where NGC occurs much more extensively than in Standard Japanese.