Recent development of plural logic is good news for students of the semantics of languages that have no systematic distinction between singular and plural, such as Japanese. But plural logic is applicable only to countable predicates; it is not applicable to non-countable predicates. Thus, the first question that we must settle before we can apply plural logic to Japanese is to make sure that the language has countable predicates.

I argue that Japanese indeed has countable predicates and that they can be recognized by a kind of numeral suffixes which can modify them. Japanese numeral suffixes are divided into three classes: (1) sortal suffixes, or classifiers; (2) unit-forming suffixes; and (3) measure suffixes. These classes can be distinguished from each other by some simple tests. I argue that a sortal suffix’s contribution to the meaning of a sentence in which it occurs is not to its truth-conditional content but only to its conventional implicature and that a noun which typically occurs with a sortal suffix has an individuating force by itself.