Asahi Sonorama
Due to the flooding of the market with similar goods, many companies began going under in the 1970s because they couldn't maintain their production levels and still make a profit. Asahi Sonorama was able to improve their manufacturing technique for the sonosheets to the point where they could attach paper labels to them, calling them "punch sheets" instead of "sonosheets". They also improved the sound quality, allowing them to release anime and tokusatsu picture books with the included punch sheet in stereo instead of mono sound. In 1975, Asahi Sonorama established its "Sonorama Bunko" imprint, and in September that same year began publication of the magazine "Manga Shōnen".