Japanese n deshita in Discourse: Past Form of n desu

N deshita/datta, which is the past-tense form of n desu/da, has not been explored in depth in studies of Japanese Linguistics. The present study examines a large corpus, and explores the cases of n deshita/datta used for past events and situations. The findings of the present study show that out of the 167 cases of n deshita/datta used for past events and situations in the corpus, 63 cases (37.7%) co-occurred with grammatical elements that require past-tense connections for the preceding item such as the sentential ending particle kke, the tara structure, and the tari structure. For the cases of n deshita/datta that co-occurred with kke, tara, or tari, it was concluded that the grammatical restrictions arising from these elements triggered the occurrences of n deshita/datta. On the other hand, 104 cases (62.3%) occurred without any grammatical elements that require past-tense connections. These cases of n deshita/datta in the corpus were used to express the speaker’s recollection of previously held knowledge, or as part of confirmation seeking utterances for previously held knowledge.