The year was 2001. You just got your hands on Pokémon Crystal, the definitive Johto experience, but there was a massive problem. Celebi was basically a ghost. Unless you lived in Japan and had a Mobile Adapter GB, that mythical forest encounter was locked behind a digital wall. That’s where the Gameshark came in. It was that chunky, gray (sometimes clear) plastic brick you shoved into your Game Boy Color, praying it wouldn’t wiggle and crash your game while you were halfway through the Elite Four.
Honestly, using crystal version gameshark codes back then felt like dark magic. It still does. Even now, with hardware like the Analogue Pocket or high-end emulators, people are still hunting for that one specific string of hex values to finally catch a shiny Suicune or skip the tedious grind of leveling up a Larvitar at Mt. Silver.
But here is the thing: Crystal is notoriously finicky. It’s more fragile than Gold or Silver because of the internal clock and the animated sprites. If you put in a bad code, you aren't just getting a Weird Egg; you're potentially wiping your entire 100-hour save file or turning your PC boxes into a graveyard of glitched "decamarks."
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Why Crystal Version Gameshark Codes Still Matter in 2026
You might think nobody plays this anymore. You'd be wrong. The retro gaming community is massive, and Crystal is widely considered the peak of the 8-bit era. People want the "authentic" experience, but they don't want the authentic 200-hour grind.
Most people use codes for three specific things. First, the Celebi event. It’s arguably the most famous use of a Gameshark in Pokémon history. Second, the "Shiny" modifier. Because shininess in Generation II was determined by Individual Values (IVs), a specific code can force a wild encounter to have the exact stats needed to sparkle. Third, the "Walk Through Walls" glitch. It’s fun, it’s chaotic, and it lets you see things the developers never intended you to see.
But don't just go copy-pasting every code you find on a dusty 2004 forum.
The Game Boy’s RAM is a messy place. When you activate a code, you are telling the hardware to "overwrite" a specific memory address with a new value. If that address happens to be your Trainer ID or your current location, and you change it to something the game doesn't recognize? Poof. Your save is gone. Or worse, your character gets stuck in a black void.
The "Must-Have" Codes for Every Johto Run
Let's get into the actual strings. These are the ones that actually work without immediately nuking your cartridge.
The GS Ball (Celebi Event)
The most legitimate-feeling "cheat" is enabling the GS Ball event. Instead of just "teleporting" Celebi into your party—which feels cheap—this code triggers the actual script. You talk to Kurt, wait a day, and then take the ball to the Ilex Forest shrine.
The Code: 010173D0
This puts the GS Ball in your "Key Items" pocket. Once it's there, you can play the game as if you were at a Nintendo event in Tokyo back in the day. It’s the "purest" way to cheat.
Infinite Rare Candies
Grinding in Crystal is a nightmare. The level curve after the eighth gym is basically a vertical cliff. If you want to get your team to level 50 for the Red fight without spending ten hours in the tall grass, you need the item slot modifier.
The Code: 0120B9D5 (Slot 1)
You have to be careful here. This changes the first item in your PC to Rare Candies. If you have something important there, move it first. Also, make sure the quantity code (0163BAD5) is active, or you'll only have one candy, which defeats the point.
Catching Any Pokémon (The Wild Encounter Mod)
This is the big one. It’s a two-part process. You have to tell the game "Hey, the next thing I run into is going to be X."
- Input the master code: 01xxEDD0
- Replace the "xx" with the ID of the Pokémon you want.
For example, if you want a Tyranitar early, you’d use F8. If you’re hunting a Lugia, it’s F9. It’s basically a God mode for your Pokédex.
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The Great "Corruption" Myth: Is it Dangerous?
Is it going to set your Game Boy on fire? No. Is it going to "corrupt" your cartridge forever? Almost never.
Most "corruption" is just the game being confused. If you save your game while a "Walk Through Walls" code is active and you’re standing inside a tree, when you reload without the Gameshark, the game checks your coordinates, realizes you shouldn't be there, and crashes. That’s not a broken cartridge; that’s just a user error.
However, there is a real risk with the "Box" codes. In Crystal, the PC storage system is incredibly complex. If you use a code to generate a Pokémon and its "checksum" doesn't match, you can end up with a "Bad Clone." These can spread. They can mess up the graphics of other Pokémon in your box. If you see a Pokémon named "??????????", do not put it in your party. Release it immediately. Seriously.
How to Input Codes on Modern Hardware
If you’re using an emulator like mGBA or BGB, you don't actually need the physical hardware. You just go to the "Cheats" menu. But there’s a catch: most emulators prefer "Game Genie" or "Action Replay" formats.
Gameshark codes are 8 digits long. They always start with 01. This prefix tells the system "Write this value to this RAM address." If you see a code starting with something else, it might be for a different version of the game (like the European or Japanese ROMs). Always double-check your region. A US code will not work on a UK version of Crystal. It’ll just scramble the colors and make the music go high-pitched. Which is actually kind of terrifying at 2 AM.
Shiny Pokémon: The Math Behind the Cheat
In later games, being "Shiny" is just a toggle. A 0 or a 1. In Crystal, it’s tied to the Pokémon's DVs (Determinate Values). To make a Pokémon shiny with a code, you actually have to change its Attack, Defense, Speed, and Special DVs to very specific numbers:
- Speed, Defense, and Special must be 10.
- Attack can be 2, 3, 6, 7, 10, 11, 14, or 15.
This is why "Shiny Codes" are often four or five lines long. They are rewriting the DNA of the Pokémon. If you only use one line of the code, you might end up with a Pokémon that has 0 HP but is technically "shiny." It'll faint the second it enters battle.
Common Mistakes Everyone Makes
I've seen it a thousand times. Someone inputs twenty codes at once, hits "Start," and wonders why their screen is white.
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Don't be that person.
The Game Boy Color has a tiny brain. It cannot handle twenty simultaneous memory overrides. If you're trying to get Infinite Money, the GS Ball, and a level 100 Mew all at once, you're asking for a crash. Use one code. Save. Turn the Gameshark off. Input the next one. It’s tedious, but it saves you from losing your progress.
Another big mistake is the "Master Ball in Slot 1" trick. People forget that their bag might be full. If your bag is full and you force an item into a slot, the game might overwrite your "Map Data" instead. Suddenly, every time you walk into a building, you end up in the middle of the ocean. It sounds funny until you realize you haven't saved in three hours.
Practical Steps for a Safe "Cheated" Playthrough
If you’re going to mess with crystal version gameshark codes, do it with a plan. Don't just wing it.
- Backup your save. If you're on an emulator, export the .sav file. If you're on real hardware, use a Joey Jr. or a similar device to dump your save to a PC.
- Test in a "Burner" box. If you're spawning Pokémon, put them in Box 14. Keep your "real" team in Box 1. If Box 14 gets glitched, it’s isolated.
- The "Save and Reset" Rule. After applying a permanent change (like giving yourself the GS Ball or an item), save the game, turn off all codes, and restart the console. If the game loads normally, the "cheat" is baked in and safe.
- Avoid "Auto-Win" Battle Codes. These are the most unstable. They interfere with the game's battle engine, which is already working at 99% capacity. They are the leading cause of "Blue Screens" on the Game Boy.
Crystal is a masterpiece. It doesn't need cheats to be good, but sometimes, we just want to relive the mystery of the Celebi event or finally own that Shiny Charizard we dreamt of in fourth grade. Just respect the hardware. The Game Boy is an old machine, and it doesn't like being told what to do. Treat the memory addresses with a little respect, and you’ll be fine.
Go get that GS Ball. Just... maybe don't use the "Walk Through Walls" code while you're on the Magnet Train. That never ends well.