The study described in this article aims to determine the usefulness of YouTube grammar explanation videos for L2 German learners in Japan. To this end, nine learners (CEFR A2) of an L2 German course at Hiroshima University participated in a written survey in which they rated ten videos on two-sided prepositions and reflexive verbs in terms of their usefulness for studying L2 German grammar. The results of the survey indicate that the respondents would rather use the selected videos to consolidate grammatical topics already covered in class than to acquire grammatical structures with which they are not yet familiar. Regarding the technical and didactic characteristics of the YouTube videos examined in this study, it was considered helpful if the content was presented concisely and the explanations were illustrated with subtitles, markers, or other types of visualisation. On the other hand, it was considered a hindrance if the presenter did not appear visually in the video, if written presentations were difficult to read, and if there were not enough example sentences or exercises. Although it was generally considered stimulating to receive instructions in German from different native speakers, some participants also expressed a desire for explanations in their L1 Japanese. Therefore, the conclusion was that grammar videos with explanations in learners’ L2 should be an optional extra rather than a compulsory element within flipped learning approaches.