Konishi Shozo invented the Filmon Sound Belt (the name is a contraction of "film" and "phone") in 1937 with the goal of increasing the capacity of audio recording (Anazawa 2014, pp. 16–18). At the time, a typical 10 inch, 78 rpm record could hold about 3 minutes of sound. The groove in a Filmon belt was incised in a loop of 35 mm unperforated celluloid film. The loop was 13 meters long and the groove wrapped around it 23 times. At a playback speed of 6.2 meters per second, it could hold up to 35 minutes of audio.

Not surprisingly, the process of molding the recording was more complex than stamping a shellac or vinyl disc. It involved creating an extended metal master and attaching it to form a helix on the interior of a metal cylinder, then heating and pressing a plastic cylinder against the matrix to transfer the grooves. The helical impression on the plastic cylinder was then cut out to form a single extended strip. Its ends were brought together with the grooves aligned and the meeting point was heated. A shorter version of the matrix was applied to refine the joint, thus avoiding an audible artifact (Konishi 1938).

As many as 120 titles were recorded for sale (Ijima 2012). A rare recording of Helen Keller's voice was made during a visit to Japan in 1937 (Ijima 2011).

The Filmon was taken off the market by 1940, a failure due to material shortages in the leadup to World War II as well as the requirement for a special player incompatible with standard disc records.