An add-on for the Famicom, called the Famicom Disk System, was released exclusively in Japan, on February 21, 1986. It used proprietary floppy disk games called “Disk Cards” instead of the standard game cartridges used on the Famicom. It was created in response to consumers wanting to be able to save their progress in games. The Disk System had lifetime sales of 4.4 million by the time it was discontinued in 1990, making it one of the best-selling console add-ons of all time!
