The first "Walkman" stereo cassette player, which revolutionized the way we listen to music. The Walkman became a huge hit, contrary to internal and external concerns that it would not sell well without the recording function, and created a new lifestyle.
Sony co-founder Masaru Ibuka wanted to "listen to music in stereo on an airplane while traveling abroad," so he had a monaural tape recorder converted into a stereo version. Akio Morita, another founder of Sony, who had tried out the modified machine, said, "This is interesting! It would satisfy the wishes of young people who want to enjoy music all day long." His business instincts dictated that the Walkman should be commercialized as soon as possible, and he decided to go with just the playback function. At the same time, ultra-lightweight headphones were being developed, and the combination of these headphones and the Walkman was completed in 1979 as a palm-sized stereo player with headphones. An ingenious advertising campaign was launched to promote the new lifestyle of enjoying stereo sound anytime, anywhere. This new way of enjoying music quickly captured the hearts of young people, and the Walkman created a new market for the headphone stereos.

The world's first portable CD player. After the release of the world's first compact disc player, the CDP-101, in 1982, the theme for engineers was to develop a "smaller CD player" that would make it easier for anyone to enjoy digital sound. The general manager of the General Audio Division at the time, showed his staff a wooden model that was 13.4 cm square, about 4 cm thick (the size of four CD software jackets), and told them to use it to produce sound. The engineers reduced the number of parts and power consumption, developed a "one-chip LSI" in cooperation with related departments, and made the optical pickup smaller and thinner, thereby achieving the target size. The player was completed priced at less than 50,000 yen, it became a big hit, and the popularity of the CD accelerated rapidly, leading to a reversal of the analog record.

A new generation of personal audio using small discs. The first "MD Walkman" was resistant to vibrations when carried, and could be used to instantly recall songs to be played.
After the development of the CD, Sony's technical team worked to develop an optical disc that could be recorded in the same way as magnetic tape. In 1986, the company commercialized the WO (Write Once Disk = an optical disk that can store information only once), and in 1988, the MO (Magnet Optical Disk = a magnetic optical disk that can be rewritten as many times as needed), which were used to record information. However, in 1990, the development of a new music recording media was initiated with the idea that we should create an alternative to the compact cassette that could record and play back music using a smaller disc than the CD.
Utilizing the magneto-optical recording technology for MOs that had been cultivated within the company, two years later, a miniaturized optical disc that could record like a cassette tape and be instantly cued with digital sound like a CD, was released. The disc is enclosed in a cartridge for easy portability, and is equipped with a shockproof memory to prevent skipping when carrying the disc. Purpose of using CD's was "to listen to sound in a relaxed manner" and MD's was "whenever, wherever, and easy, like a Walkman."