Abstract
In this paper we have attempted to identify the source sentence ofwhat is called the unagi-bun. After a brief description of typical unagibunsentences, we have examined six hypotheses on the source of theunagi-bun. They are the no-da, copula, response, cleft sentence, propredicationand ellipsis hypotheses.
We have refuted the no-da hypothesis from the semantic point ofview; copula and cleft sentence hypotheses because of their requirementof two variables in the sentence; response hypothesis because of itsrequirement of a question as a precondition for the existence of theunagi-bun; and propredication hypothesis in terms of the boundness ofthe sentencehood marker da, its emptiness in meaning and its identicalbehaviour in optionality between the unagi-bun and ordinary da-patternsentences.
We have then confirmed Kuno's ellipsis hypothesis based on thesyntactic asymmetry of su-ru ‘do’ and da in substituting for active andstative predicates. Finally, we have argued for optionality of da-attachment and proposed this rule as a global convention.
