This paper investigates the Nominative/Genitive alternation statistically, and provides some interesting findings. First, a large number of native speakers of Japanese disallow the Genitive Subject in complex NPs. Second, two varieties of Japanese are observed with respect to the alternation: (1) a variety that disallows the Genitive Subject in the configuration in which the alternation has been considered to be potentially possible, and (2) a variety that allows the Genitive Subject in the same configuration, but keeps the transitivity restriction. Third, variety (2) disallows the alternation when the verb is a pseudo-transitive that has an Object marked Dative. Fourth, variety (2) disallows the alternation in comparative clauses. Fifth, in variety (2), adjacency between the verb and the Genitive Subject has no effect on the alternation.