This article explores the possibility of learning Japanese while sleeping and examines the science behind sleep learning. It is possible to learn Japanese in your sleep, but certain conditions must be met for it to be effective. Benefits of sleep learning include improved memory and recall, while potential risks include overstimulation, distraction and repetition. Research suggests that audio recordings can aid language acquisition during sleep, but further research is needed before any definitive conclusions can be drawn. Tips are provided for successful sleep learning Japanese.