The Microcassette was introduced in 1969 by Olympus for dictation purposes, but in 1981 and 1982 several devices were introduced that used the Microcassette for music recording and playback.
Several personal stereo devices, similar to the Sony Walkman were introduced, such as the Olympus SR-11, and there were also several Microcassette decks for Hi-Fi separates systems from brands such as JVC, Sanyo, Technics and Sony.
The Microcassette for music was a little different to the standard Microcassette and used metal tape (coated with pure metal particles rather than oxide) which had been introduced for the Compact Cassette in 1979 as this offered higher sound quality. Many of the new Microcassette music devices offered Dolby noise reduction, and of course this version of the Microcassette offered stereo sound.
A few pre-recorded tapes were released (mostly in Japan), but the format failed to take off and seems to have disappeared fairly quickly. Even at the time the tapes had limited availability and were expensive, and it’s now hard to find original metal tape Microcassettes.
Despite being used for music playback in its metal-tape form, the cassette seen in the 1971 film ‘A Clockwork Orange’ was the similar Mini-Cassette format and not a Microcassette.