You’re staring at the screen. Your Pidgeotto is out, the HP bar is flashing red, and you just need one hit to end the fight. You click Gust. It misses. Wait, what? In the original Generation I Pokemon games (Red, Blue, and Yellow), there’s this specific, glitchy math that makes moves fail when they absolutely shouldn’t. If you’ve ever gone down the rabbit hole of competitive mechanics or speedrunning, you’ve likely run into the infamous Gust of Wind 93 102 phenomenon—or more accurately, the internal index numbers and the "1 in 256" glitch that defines them.
Honestly, it’s a mess.
Gen I was held together by digital duct tape. When we talk about Gust of Wind 93 102, we are looking at the intersection of Move Index 93 (Confusion) and Move Index 102 (Mimic), and how the game’s engine handles accuracy across the board. Most people think a move with 100% accuracy will always hit. They’re wrong. Because of how the original Game Boy processed numbers, a 100% accuracy move actually has a 255/256 chance of landing. That’s roughly a 99.6% success rate.
That 0.4% chance of failure is the bane of every Nuzlocke player's existence.
The Math Behind the Miss
Let’s get technical for a second, but keep it simple. The Game Boy’s CPU, the Sharp LR35902, is an 8-bit processor. This means it loves the number 255. In the code for Pokemon Red and Blue, accuracy is calculated by comparing a random number (0 to 255) against the move's accuracy value.
Here is where the developers tripped up.
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If the random number generated is strictly less than the accuracy value, the move hits. If you have a move like Gust (which is Index 16, by the way, but often grouped in discussions about early-game flying/normal moves), and it has an accuracy of 250 (which translates to roughly 98% in modern terms) or even a "perfect" 255, the check still fails if the random number generated is exactly 255.
Basically, the game can’t check if 255 is less than 255. It just fails. This "1/256 glitch" means that in the original Kanto adventures, there is no such thing as a guaranteed hit, unless you're using Swift.
Why Index 93 and 102 Matter
You might be wondering why the numbers 93 and 102 keep popping up in these legacy data discussions. In the internal move list of the ROM, every move has an ID.
- Move 93 is Confusion. A staple psychic move.
- Move 102 is Mimic. A weird utility move.
When researchers look at Gust of Wind 93 102 data, they’re often looking at the hex values in the game’s memory that dictate how these moves behave during a "Gust" or wind-based animation sequence. In the early games, Gust wasn’t even a Flying-type move; it was Normal-type. It didn't become Flying-type until Generation II. This caused massive confusion (no pun intended) for players trying to hit Fighting-types for super-effective damage only to realize the "wind" was doing neutral damage.
If you look at a hex editor for Pokemon Red, the data structure for moves is packed tight. If the memory shifts—which happens during certain glitches like the "Select" glitch in the Japanese versions—the properties of Move 93 can bleed into Move 102. You end up with a Gust of Wind that has the side effects of Confusion or the variable nature of Mimic.
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Speedrunning and the RNG Nightmare
Speedrunners like Werster or Gun_N_Rose have lost world-record-pace runs to this exact 255/256 error. Imagine you're at the end of a two-hour run. You use a move with 100% accuracy. The game rolls a 255. You miss. You die. Run over.
It sounds like a small margin. 0.4% isn't much, right? But over the course of thousands of attacks in a single playthrough, you are almost statistically guaranteed to see this glitch at least once. It makes the "Gust of Wind" feel less like a gentle breeze and more like a chaotic gamble.
There’s also the matter of the "Accuracy/Evasion" bug. If your opponent uses Double Team or Sand Attack, the game doesn't just lower your chances; it manipulates those same 8-bit values. Because of the way the floor and ceiling of these numbers are handled, you can actually reach a point where your accuracy "wraps around," though that's more common in later glitch-heavy setups.
Comparing the Generations
It’s wild to see how far we’ve come. In Modern Pokemon (Gen 9, Scarlet and Violet), the accuracy check uses a 0-100 scale that actually functions.
- Gen I: 1/256 chance to miss anything. Gust is Normal-type.
- Gen II: Gust becomes Flying-type. The 256 glitch is patched out.
- Gen III: Moves get "Abilities" like Keen Eye to prevent accuracy drops entirely.
If you’re playing on a Virtual Console version of the old games today, these quirks are still there. Nintendo and Game Freak didn't patch the ROMs for the 3DS or Switch releases; they left the "authentic" experience intact. That means the Gust of Wind 93 102 logic—the messy, 8-bit, glitch-prone heart of Kanto—is still beating.
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How to Handle Low-Accuracy Scenarios
So, what do you do if you’re playing through Yellow or Crystal and you’re worried about these weird accuracy rolls? You can't fix the 1/256 glitch. It's hard-coded. But you can mitigate the risk.
First, stop relying on moves with base accuracy below 85. In Gen I, a move with 80% accuracy feels more like 60%. If you combine that with the 255-roll glitch, you're asking for a headache. Second, remember that Swift is the only move that ignores the accuracy check entirely. It bypasses the random number generation by skipping the check block in the code.
Most players just brute force it. They spam A and hope for the best. But if you’re playing a high-stakes match, understanding that Move Index 93 (Confusion) and its peers are subject to these invisible failures changes how you value "safe" plays.
Actionable Takeaways for Retro Players
If you are diving back into the classic games, keep these points in mind to avoid being a victim of the RNG:
- Swift is your insurance policy: Keep it on at least one Pokemon to finish off low-HP enemies where a miss would mean your defeat.
- The 1/256 rule is absolute: Never assume a kill is guaranteed unless the move cannot miss. Even "Sure-hit" moves in later games didn't exist in the same way here.
- Type matters less than you think: In Gen I, Gust won't help you against Bruno's Machamp because it's Normal-type. Don't waste the turn.
- Badge Boosts: Did you know that in Gen I, getting badges actually boosts your stats in-battle? The Boulder Badge boosts Attack. This can help you over-level the need for multiple hits, reducing the number of times you have to roll the dice on accuracy.
The complexity of these old games is hidden under layers of simple sprites and chiptunes. Whether it’s the weird interaction of move indices 93 and 102 or just a stray gust of wind missing at the worst time, the math defines the journey. You just have to hope the 8-bit gods are on your side.
To really master the old-school mechanics, try a "No-Pokecenter" run. It forces you to learn which moves are statistically the most efficient and which ones, like the glitchy Gust, are better left forgotten in the move list.