Vermilion Gym appears in all games that include the Kanto region, appearing much the same in each: the main room contains 15 trash cans in three rows and five columns, and Trainers are scattered about this room. Another room lies behind the main room, guarded by electric doors in Generation I, and an electric fence from Generation III onward. The only way to get in the final room, where Lt. Surge is located, is to find two hidden switches inside the trash cans. Discounting glitches, the second switch is always next to (orthogonally adjacent to) the first switch. If the first switch is found, but the player incorrectly guesses the second one, the traps reset.
The first switch can be in one of eight cans as in Red and Blue.
If the first can was one of the four corners:
There is a 25% chance that one neighbor contains the second switch, a 25% chance that the other neighbor contains the second switch, and a 50% chance that both neighbors contain the second switch (in which case either choice will unlock the door).
If the first can was the one in the second column:
There is a 50% chance that the west and north neighbors both contain the second switch, a 25% chance that only the south neighbor contains the second switch, and a 25% chance that only the east neighbor contains the second switch.
If the first can was the one in the fourth column:
There is a 50% chance that the west and north neighbors both contain the second switch, and a 50% chance that the south and east neighbors both contain the second switch.
If the first can was the top can of the middle column:
Due to yet another glitch, the game attempts to randomly pick from 256 possible pairs of cans for the second switch, most of which correspond to blank neighbor data or partially-invalid data about the neighbors of other cans. As a result, there is a 216/256 (~84%) chance that only the top-left can has the second switch, a 2/256 (~0.8%) chance that no can has the second switch at all, and a 38/256 (~15%) chance that either one or two cans anywhere among the four rightmost columns have the second switch (with uneven probability).
If the first can was the bottom can of the middle column:
The above glitch applies but with slightly different data, resulting in a 225/256 (~88%) chance that only the top-left can has the second switch, a 1/256 (~0.4%) chance that no can has the second switch at all, and a 30/256 (~12%) chance that either one or two cans among the four rightmost columns have the second switch.
The fourth can in the bottom row is an empty red trash can, while the second can in the middle row is an empty blue trash can. When defeated, the Trainers in the Gym hint that a can next to the blue can contains a switch, while none of the cans next to the red can contain a switch. Together this narrows the switch locations down to two pairs of possibilities, with the correct locations being the center trash can and the can directly north of it. These locations will remain fixed even if the traps are reset. The two switches can be activated in either order.
The Vermilion Gym first appeared in Electric Shock Showdown. Ash and his friends arrived at the Gym for Ash's third Gym battle, with Surge calling Ash a baby and calling him out on not having evolved his Pikachu yet. Ash was determined to prove Surge wrong, but his Pikachu was easily defeated by Surge's Raichu. Later, Ash challenged Surge to a rematch, having figured out that Raichu's weakness was that it had evolved too fast, never learning the speed moves it could only learn as a Pikachu. With his superior speed and new Agility and Quick Attack, Ash's Pikachu was able to overwhelm Surge's Raichu and defeat it, earning Ash the Thunder Badge and Surge's respect.
In Destination: Coronation!, over a thousand episodes later, Ash revisited the Gym in order to have his first World Coronation Series match against Visquez, a substitute Gym Leader looking after the Gym while Lt. Surge was away training. Upon arrival, Ash learned that Visquez had heard of his Vermilion Gym battle from Lt. Surge. After a tough battle, Ash emerged victorious, increasing his World Coronation Series ranking.
Raichu is Visquez’s first known Pokémon. He was first seen battling a Trainer's Hypno and defeated it with Volt Tackle. After the battle, Raichu was lifting a dumbbell alongside Visquez when they received word of a Trainer coming to challenge them.
Raichu was the first Pokémon used in Visquez battle against Ash, where he went up against Pikachu before Pikachu was recalled in favor of Gengar. After a hard-fought battle, Raichu was defeated.
Electrode is Visquez‘s second known Pokémon. It was first used to battle Ash's Gengar and was able to defeat it before going up against Pikachu. Despite Electrode's great speed, Pikachu managed to defeat it. Electrode attempted to take Pikachu down with it, only for Pikachu to protect himself, thus leading to only Electrode going down and causing Visquez to lose the match.
The Vermilion Gym appeared in Vermilion City, where Satoshi challenged Lt. Surge. The Gym battle was conducted between Satoshi's Charmeleon and Lt. Surge's Electabuzz. Even though Charmeleon was driven into a corner, it was able to use a piece of the barbed-wire fence surrounding the arena to tie Electabuzz up and then finish it off with a Fire-type attack. After the battle, Satoshi received a Thunder Badge from Lt. Surge and an HM01 (Cut) from the captain of the S.S. Anne, whom he had met earlier and was friends with Lt. Surge.
In the TCG
The Vermilion Gym was featured in the TCG as both a Japan-exclusive Theme Deck and as a card. The following is a list of cards mentioning or featuring Vermilion City Gym in the Pokémon Trading Card Game.
Vermilion Gym Cards listed with a blue background are only legal to use in the current Expanded format. Cards listed with a silver background are legal to use in both the current Standard and Expanded formats.
In the English versions of Pokémon FireRed and LeafGreen, the Gym guide mistakenly refers to the Flying type as the Bird type. This is likely an oversight derived from his dialogue in the English versions of the Generation I games, where he instead refers to Flying-type Pokémon by describing them as "bird Pokémon"; in the Japanese versions of the Generation I games and FireRed and LeafGreen, he clearly mentions types and correctly identifies the Flying type as ひこうタイプ (the Bird type is とりタイプ in Japanese).