Introduction

One of the most difficult aspects of the study and use of Japanese grammar involves the distinction between ga and wa. Textbooks commonly explain that the primary function of ga is to mark the subject, although, as seen in Chapter 7, ga-marked NPs do not always qualify conceptually as subjects. On the other hand, wa is said to mark a topic. In ordinary language, both subject and topic can be loosely defined as the focal point of discussion. Therefore, subject and topic do overlap in function – that is, many subjects are also topics, and many topics are commonly expressed as subjects. In linguistics, however, subject and topic refer to drastically different concepts. Subject is a grammatical relation held between a given constituent, typically an NP, and the predicate. That is, the scope of a subject is limited to a clause, or to a sentence if the sentence is mono-clausal. Topic, on the other hand, references a much broader notion. It is normal to consider the topic of a paragraph, the topic of a chapter, or even the topic of an entire book. In other words, the scope of a topic is a discourse (or a text); that is, a sequence of sentences organized by a specific purpose.

This difference in scope between subject and topic makes elucidation of ga and wa a challenge because they do not necessarily contrast on the same bases. When a sentence is examined in isolation, ga and wa can often be used interchangeably; however, when that same sentence is embedded in a discourse, either ga or wa might not be usable. Another reason for difficulty is that the selection criteria for these particles are not mutually exclusive. In the same sentences, ga might be appropriate according to one criterion, but wa preferable according to another. To put it differently, the distinction between ga and wa is primarily a matter of information packaging, i.e. how the message is sent, rather than the content of the message itself (Chafe 1976: 28).