Somewhere in a closet or a shoebox, there’s a Game Boy cartridge that still remembers your name. Or it did. A lot of people who dug their old Pokémon Blue cartridge out in the last few years flipped the power switch, watched the logo scroll down, hit “Continue,” and got nothing. No save file. No error message. Just a blank slate, like the game forgot it ever met you.
That’s not the Game Boy failing. That’s a battery dying, and it’s been dying since roughly the day the cartridge left the factory.
Every Game Boy or Game Boy Color game with a real save feature, not a password screen, keeps its own battery soldered straight onto the circuit board inside the cartridge. It has nothing to do with the two AA batteries in the console, which only power the screen and the processor. Save memory needs a constant trickle of power to hold data even with the system switched off, so Nintendo and its licensees tucked a coin cell under the label of every cartridge that needed one. Most used a tabbed CR1616. Pokémon Crystal, which also had to run an internal clock, got the slightly beefier CR2025. Nobody expected an owner to swap these out. They were built to last “long enough,” and in 1998, nobody was designing around the idea that people would still be playing these carts in 2026.
Lithium coin cells don’t last forever, and they don’t all fail on the same schedule. Some cartridges still hold a save today. Others gave out a decade ago. The bigger risk isn’t even the dead save. It’s the leak. A spent battery can weep electrolyte onto the board underneath its label, and left sitting for years, that corrodes the traces and can take out the whole cartridge, not just the memory.
None of this is a Pokémon-specific problem. Nearly every Game Boy RPG, strategy game, or anything with a “continue” option relies on the exact same tiny battery hiding under the exact same label. Pokémon just sold enough copies, more than 31 million worldwide across Red, Blue, and Yellow combined, that it’s the cartridge most people have actually gone digging for.
Battery-backed saving itself didn’t start on the Game Boy. Nintendo pioneered it on the NES with The Legend of Zelda back in 1986, letting players pick a quest back up across sessions instead of scribbling down a password. The idea just got smaller, cheaper, and a lot more common once it moved into a handheld people carried in their backpacks.
Here’s where it actually matters for grading. A numeric grade on a Game Boy cartridge is built from what a company can see and verify from the outside: label wear, corner rounding, shell condition, print quality. It says nothing about whether the battery buried inside is still holding a charge, because there’s no way to check that without opening a cartridge a collector generally wants left sealed or intact. A cartridge can pull a flawless grade on looks and have a completely dead save battery underneath, and both of those things can be true of the exact same piece of plastic.
That distinction is worth knowing before you buy, not after. A collector chasing display value cares about one thing. Someone who actually wants to load up their old save file cares about another, and a high grade doesn’t promise the second one. If you’re curious how a grade actually gets built in the first place, box, cartridge, manual, and how they’re weighed against each other, that’s covered in detail on our how it works page.