The goal of this paper is to investigate the binding properties of casin ``self``which has been regarded as X0 reflexives in Korean. According to Cole et al (1990), X0 reflexives in East Asian languages such as ziji ``self`` in Chinese and casin ``self`` in Korean allow to be bound to the long distance antecedent as well as the local antecedent. However, after reviewing the behaviors of X0 reflexives in Korean, it was found that they did not always maintain the properties of reflexives and the characteristics of "long distance binding". Thus, this paper claimed that casin ``self`` should be re-categorized as both pronouns and reflexives.