On this day 1979: Sony introduced the walkman to the market. It was the first personal stereo cassette player and the pioneer innovation that would revolutionise portable audio. Sony’s legendary co-founder Masaru Ibuka was a music lover who often carried a stereo tape recorder along on his travels. But the device was heavy and somewhat inconvenient for his frequent trips. So Ibuka asked his deputy Norio Ohga to come up with something smaller. By then Sony already had the pressman, a portable tape recorder for journalists. So Ohga made a prototype which was a playback-only device for his boss to take on his next foreign trip. Though its battery ran out half way, Ibuka was greatly impressed with the sound quality and portability. So he floated the idea of going commercial with the product to the board. When objections were raised about the salability of a cassette device only for playback, Ibuka asked ”Don’t you think a stereo cassette player that you can listen to while walking around is a good idea?”. His query will prove to be one of the great litotes in business history. Within 4 months Sony engineers developed the walkman which was introduced to the market at $150 before the summer vacation on July 1, 1979. The initial sale of 3,000 units for the first month seemed disappointing since 30,000 units had been produced. But an aggressive marketing campaign was launched and representatives approached pedestrians on the streets of Tokyo to gave them a chance to listen to the Walkman. The remaining stock sold out before the end of August signaling the beginning of one of Sony’s greatest success stories. Over 400 million Walkman portable music players have been sold, 200 million of them cassette players until Sony retired the classic cassette tape Walkman in 2010.