Which video game was the first to include a battery-backed save system?

The Legend of Zelda was the first video game to include a battery-backed save system.

Nintendo released The Legend of Zelda for the Famicom Disk System in Japan in 1986 and for the Nintendo Entertainment System in North America in 1987. The cartridge version contained battery-backed static RAM, allowing players to save progress inside the game rather than restarting from the beginning each time.

This feature suited Zelda's large, exploratory design. Players could uncover dungeons, collect equipment, and return later without losing their progress. Earlier games sometimes used passwords or relied on the player completing the experience in one sitting, but Zelda made persistent cartridge saves a defining console feature.

The game is also associated with the gold-colored NES cartridge used in North America. Later Nintendo titles, including role-playing games, adopted battery-backed saves widely, although modern cartridges and consoles generally use flash memory or internal storage instead of replaceable batteries.