This study investigates how implicit and explicit learning and knowledge are associated, by focusing on the salience of target form--meaning connections. The participants were engaged in incidental learning of artificial determiner systems that included grammatical rules of [± plural] (a taught rule), [± actor] (a more salient hidden rule), and [± animate] (a less salient hidden rule). They completed immediate and delayed post-tests by means of a two-alternative forced-choice task with subjective judgments of source attributions. Awareness during the learning phase was identified through analysis of thinking aloud protocols. The results did not support a one-to-one relation between either explicit learning and conscious knowledge, or implicit learning and unconscious knowledge; rather, they indicated that implicit and explicit learning are intricately linked to conscious and unconscious knowledge mediated by the salience of form-meaning connections in target items. This result also suggests the possibility of the later emergence of knowledge without any conscious awareness of it.