I recently discovered 高校講座 (high school course) on the NHK website. It appears to be full of different high school-level courses, many of which are in the form of slide shows with a narrator. However, some of them are televised mock lessons, such as the one I started watching - 現代の国語 (Contemporary Japanese). I find it really great so far, but the level of conversation is at least higher intermediate, not suitable for beginners. I would say it’s still above my level as well, although I can usually understand most of what the high schoolers and the presenter are saying. The teacher’s speaking pace and some vocabulary are a bit too advanced for me though.
現代の国語 has 20 episodes, 20 min each, so that’s plenty of listening material. All episodes have Japanese subtitles, which you can enable in the video player.
If you were already familiar with this website, what courses have you watched? What courses do you recommend?