Book excerpt: The objective of this thesis is to describe the synchronic system of tense and aspect in Old Japanese. Japanese grammarians studying the tense/aspect morphology of Old Japanese usually identify four suffixes ( -(ye) ri, -tari, -tu, and -nu) as kanryo 'perfect' markers and two suffixes ( -ki and -kyeri) as past tense markers. However, this analysis results in a typologically unattested temporal system, characterized by an implausibly rich inventory occupying a small semantic space. The traditional analysis is the product of an approach focusing on identifying the meanings of the suffixes based on contextual information, rather than the syntactic distribution of the suffixes with respect to the lexical semantics of the co-occurring verbs and the overall synchronic system of the language. Furthermore, previous analyses have attempted to produce a uniform analysis covering the entire 700-year period from Old to Early Modern Japanese.