Many thanks to SWLing Post contributor, April TimeLady, who writes:
To aid in my knowledge of the Japanese language I have been using SDRs and recording what I hear.
I have uploaded a collection of recordings of Japanese audio made from various SDRs, primarily those located in Japan itself. Those with 6105 kHz in the title were generally made off of American SDRs. Occasionally there will be some European and African off air recordings in there. These are in .ogg format.
Thank you for sharing your recordings with the world, April!