This is a spoken corpus, based on a series of longitudinal studies consisting of data collected from 3 Chinese and 3 Korean learners of Japanese. The title of this corpus is "Spoken Corpus of Longitudinal Research on Chinese and Korean Learners of Japanese", and the abbreviated title is "C-JAS (Corpus of Japanese as a Second Language)". The data comprises 570,000 words and about 46.5 hours worth of speech (utterance). An online system can be used to search the data for examples by morpheme unit, character string, etc.