Which disk-based Nintendo platform first received Metroid in Japan?

The disk-based Nintendo platform that first received Metroid in Japan was the Family Computer Disk System.

Nintendo released the original Metroid in Japan on August 6, 1986, for the Family Computer Disk System, commonly abbreviated Famicom Disk System or FDS. The add-on used rewritable floppy-style Disk Cards and was designed for Nintendo’s Japanese Family Computer hardware.

This release came before the game reached Western players. North America received Metroid on the Nintendo Entertainment System in 1987, followed by Europe in 1988. The Japanese disk version also reflects the original market’s use of save-capable Disk Cards, whereas Western versions used a password system to resume progress.

The Family Computer Disk System is sometimes confused with the NES because both are Nintendo platforms and the Western cartridge release became the best-known version. The Game Boy and Super Famicom were not the original Japanese platform for Metroid. The title’s exploration-focused design, mixing platforming with nonlinear discovery, later became a major influence on the Metroidvania style.