How to Beat the First Gym Leader in Pokémon FireRed and LeafGreen

Last Updated: August 6, 2021

Brock, collector of Rock/Ground-type Pokémon, is the first gym leader in Fire Red and Leaf Green. Defeating him will get you the Boulder Badge, as well as TM39, which teaches a Pokémon the move Rock Tomb. Brock's only Pokémon are both Rock/Ground-types: a level 12 Geodude and a level 14 Onix. Try to stack your party with Pokémon that are strong against Rock and Ground types: Squirtle or Bulbasaur, Mankey, Nidoran, Rattata, and Butterfree.

Part 1

Part 1 of 3:

Picking Your Pokémon

1
Know what to expect. The first Gym Leader, Brock, can be easy or relatively difficult to beat depending on which Pokémon types you have in your party. In FireRed and LeafGreen, Brock has two Pokémon: a level 12 Geodude with Tackle and Defense Curl, and a level 14 Onix with Tackle, Bind, Harden and Rock Tomb. Brock is an especially challenging fight because both of his Pokémon have defense-raising moves (Defense Curl and Harden). Your Pokémon will mostly be able to use basic physical attacks early in the game, so the battle could get progressively harder depending on how many times Brock's Geodude and Onix are able to use Defense Curl and Harden.
- Brock's Geodude only has one attack: the Normal-type attack Tackle. This means that any Pokémon should be able to knock him out if it also has a normal type attack.
2
Build a team with Pokémon that are strong against Rock/Ground types. Know which Pokémon types are strong against Rock types. You will want to stack your team with Pokémon of these types:
- Water
- Grass
- Ice
- Ground
- Fighting
- Steel
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3
Consider your starting Pokémon (Charmander, Squirtle, or Bulbasaur). The battle to come will be easier if you chose Bulbasaur or Squirtle, and it will be harder—though by no means impossible—if you chose Charmander.
- The easiest way to beat Brock is to choose Bulbasaur or Squirtle as your starter—both Water and Grass attacks do 2x damage against Brock's Rock/Ground-type Pokémon. As a bonus, Squirtle's early-game Water-type move, Water Gun, is a Special move, meaning that it won't be weakened by Brock's Pokémons' high Defense stats.
- If you chose Charmander as your starter, you may have a difficult fight—Fire types are notably weak against Rock types. You may support your Charmander with Pokémon that are strong against Rock types: Mankey (Fighting type) and/or Rattata (Normal type, but does not take 2x damage from Rock attacks).
4
Try not to use Pokémon that are weak against Rock types. Catching a Pidgey (Flying type), Caterpie, Weedle, Kakuna, Metapod (Bug types), and/or a Pikachu (Electric type) will make your team stronger in the long run, but it will only help you so much in this battle: Rock types do 2x as much damage against Fire, Flying, and Bug types.
- A team that includes Charmander, Pidgey, Caterpie, Weedle, Kakuna, Metapod, and/or Pikachu can still battle Brock and win, as long as they are of high enough levels or you carry them in great enough numbers.
- Pikachu will be very useful against the second Gym Leader, but he will not help you much against Brock. Although neither of Brock's Pokémon have a Ground-type move (which would do 2x damage against Pikachu) he will not be able to do any damage in the battle: both Geodude and Onix are immune to Electric attacks due to their secondary Ground type.
5
Consider going up against Brock with the following team:
- Bulbasuar or Squirtle level 14 (starter Pokémon); you can also train him to level 16, at which point Bulbasaur evolves into Ivysaur and Squirtle evolves into Wartortle.
- Butterfree level 12 (evolves from Caterpie and Metapod, which are found in Viridian Forest)
- Mankey level 12 (found on Route 3 near Pokémon league—west of Viridian City)
- Pikachu level 10 (found in Viridian Forest. Pikachu won't be much use against Brock, but he will come in handy for the next gym. Pikachu is very rare, so you will need to spend some serious time walking around the tall grass of Viridian Forest). (Also consider raising the Pikachu to level 26 before the second gym to learn a more powerful Electric type move)
- Pidgey level 10 (found on Route 2, on the way from Pallet Town to Viridian City. Pidgey knows sand attack, which will drop Brock's Geodude and Onix's accuracy way down).
- Nidoran level 12 (Later, you can evolve him to Nidoking for a serious power Pokémon).

Part 2

Part 2 of 3:

Training for the Battle

1
Get through Viridian Forest. Brock's gym is in Pewter City, so you will need to make it there if you want to battle Brock. Make sure to heal all of your Pokémon at a Pokémon Center before you go, and make sure to bring a few Pokéballs. While you're in the forest, take the opportunity to catch a Caterpie, a Pikachu, and perhaps even a Weedle.
2
Train your starter Pokémon to level 14. You will need to walk around in tall grass and fight every wild Pokémon that you encounter—even if it's only level 3. Fight any trainer that you meet. Keep battling wild Pokémon until your Pokémon are close to fainting, then get to a Pokémon Center before it's too late. Train your starter until it learns its powerful type-specific moves:
- If you chose Bulbasaur or Squirtle as your starter Pokémon, then you're in luck. By the time you face Brock, they should naturally learn moves that are strong against Rock types: Razor Leaf and Vine Whip (level 7) for Bulbasaur, and Bubblebeam (level 7) and Water Gun for Squirtle.
- If you chose Charmander, you might have a tougher time beating Brock. However, Charmander can do okay with its Ember attack. You can also train Charmander to level 13, when it learns Metal Claw; Metal Claw is a Steel-type move, and thus is super effective against Rock-type Pokémon.
- If you train your Charmander to level 16, when it evolves into Charmeleon, it may be strong enough to hold its own against Brock. The same goes for Bulbasaur and Squirtle, which evolve into Ivysaur and Wartortle at level 16. However, it is not always wise to rely on just one Pokémon.
3
Train a Rattata. If you chose Charmander, it is a good idea to train a Rattata: Normal types deal 1/2x damage and take 1x damage against Rock and Ground types, which will make the fight a bit easier for you. You can catch a Rattata in tall grass
4
Catch Caterpie and train it to level 10. At level 7 it will evolve into a Metapod and learn Harden. At level 10, Caterpie evolves into its final stage, Butterfree, and learns Confusion. Confusion is a powerful attack for such a low level, and having it in your roster will give you a much easier time beating Brock. Confusion is not super effective against Brock's Pokémon, but it will deal a significant amount of damage.
- You can find Caterpie and Metapod by walking around in the tall grass within Viridian Forest. It is a good idea to catch a Caterpie instead of a Metapod: Caterpie naturally knows Tackle—an attack move—whereas wild Metapod only know Harden (a purely defensive move).
5
Catch Mankey and train it until it knows Karate Chop (which it learns at level 11). A level 11 Mankey can take out Brock's level 14 Onix in two turns. Karate Chop is a Fighting-type move—super effective against Brock's Pokémon—so you should be able to easily win with it.
- If you have trouble with Brock's Onix only, then you just need to raise Mankey until it learns Low Kick. Mankey usually learns Low Kick at level 9, but there is a chance that it will learn the move at level 6. This move is helpful against Onix because the heavier the foe, the greater the damage.
- You can find Mankey on Route 22—on the way to Victory Road—which is off to the left side of the screen when you are in Viridian City. Keep following this path until you come to a patch of tall grass. Note: You will need to battle your rival here, so make sure to bring your strongest Pokémon.
6
Catch Nidoran (male or female) and train it to level 12. You do not absolutely need a Nidoran, but it will be more useful than, say, a Pidgey or a Pikachu. You can find Nidoran in the same areas that you can find Mankey: on Route 22, when you walk west/left-of-the-screen from Viridian City. Nidoran eventually evolves into Nidorino or Nidorina (depending on the gender) and then Nidoking or Nidoqueen, which are two of the most powerful Pokémon in the game.

Part 3

Part 3 of 3:

Battling Brock

1
Train until you have a strong, diverse party. You should at least have a level 12 Mankey, a level 14 Bulbasaur, Squirtle, or Charmander, and/or a level 12 Butterfree. It wouldn't hurt to have a level 12 Nidoran or Rattata. When you think your team is strong enough, you are ready to battle Brock and win your first badge.
2
Heal your Pokémon before you enter the gym. Visit a Pokémon Center and make sure that all of the Pokémon in your party are at full health. Stock up on potions—you can buy them at any PokéMart. You can use a potion to heal any Pokémon by 20 HP in the midst of battle; the act of healing takes the place of an attack turn. This is a great way to give yourself extra insurance when you face Brock.
3
Enter Brock's gym in Pewter City. Battle and defeat the first trainer that you encounter. You need to beat this trainer in order to get to Brock. This fight should give you an idea of what you will encounter when you face Brock: both trainers use only Rock-type Pokémon, although Brock's team is stronger. Once you beat this first trainer, go heal your Pokémon one last time before you challenge Brock. You want your team to be in top fighting shape.
- If you don't beat this first trainer, then you aren't ready to beat Brock. Go train your Pokémon until they are stronger.
4
Save the game before you challenge Brock. You should save the game before you enter any Gym Leader battle—or any important battle, for that matter. This way, you can always start over and try again if you mess up.
5
Challenge Brock. When you have trained your team, beaten the first Gym trainer, saved the game, and brought all of your Pokémon to full health, you are ready to battle Brock. Walk to the figure standing in the center of the Gym, and talk to him. He will say a few words, and then the battle will begin. Brock will send out Geodude first, and then Onix.
6
Start with a Pokémon that is strong against Rock types. Attack quickly and efficiently before Brock's Geodude and Onix have the chance to use their defense-boosting moves; the more times they boost their Defense stats, the harder it will be to beat them. Use the Pokémon and attacks that are most effective against Rock/Ground types. Use potions, if necessary, to keep your strongest Pokémon in the fight.
- If you have Pokémon that are strong against Rock types, use their type-specific moves. Have Bulbasaur use Vine Whip and Razor Leaf; have Squirtle use Bubblebeam and Water Gun; have Mankey use Low Kick and Karate Chop. If these Pokémon have reached high enough levels, they should make short work of Brock.
- If you have a Pidgey, repeatedly use Sand Attack to weaken the accuracy of Brock's Geodude and Onix—this will make their attacks less likely to hit. Pidgey will stand no chance against Geodude; the goal here is to make it easier for your other Pokémon to dominate the battle. Just use Sand Attack as much as possible.
7
Get TM39. When you beat Brock, he will give you TM39, which you can use to teach one of your Pokémon the move Rocktomb. This is a solid Rock-type move that lowers the opponent's speed on contact. Save this TM until you catch a Rock-type Pokémon (such as Geodude or Onix) that will be able to use the move effectively.
8
Continue your adventure. Once you beat Brock, there is nothing important left for you to do in Pewter City. Leave the city along the road to the east/right-of-the-screen. Walk onward toward Mt. Moon, which takes you to Cerulean City, and continue with the rest of your adventure.

Community Q&A

Question

How do you beat the other gym?

Community Answer

For the rock gym, Charmander learns iron claw at level 13 if you are patient enough. With Squirtle and Bulbasaur, you will get a grass/water move very early on.
Question

Does this work for Pokemon ed for Game Boy color?

Community Answer

Almost. But in red, Charmander can't learn metal claw because steel type doesn't exist in gen.1.
Question

How many times can Geodude and Onix use Defense Curl?

Community Answer

It's random. If you are lucky enough, they can use it even only once. After about six uses, this move will became useless.