Amongst the multiple and diverse meanings and functions passive constructions hold, this study shows that the primary function of passives in Japanese is to portray an event from the point of view of an affected entity. It identifies three types of affectedness in Japanese passive constructions: emotive affectedness, direct/physical affectedness, and objective affectedness.

A key contribution of this study is to reveal how Japanese passives are actually used in real contexts. In order to achieve this, detailed examination of authentic written and spoken data is conducted. Some findings of this data analysis contradict previous claims, such as the finding of a large proportion of passives with a non-sentient subject, the very low frequency of indirect passives and the appearance of a considerable number of passives in a proposition with a neutral or positive meaning.

Many previous researchers have claimed a complete and apparently transparent correlation between the syntactic and semantic distinctions of the Japanese passive. However, through analysing authentic data, it becomes evident that the correlation is much more subtle, and that is a matter of degree or a continuum, rather than a discrete, black and white issue. To reflect this view, this study proposes separate sets of categories for syntactic and semantic distinctions.