Wally will challenge you to a rival battle when you first arrive at the Mauville City Gym. After the battle, you’ll get HM06 Rock Smash from Wally’s Uncle.
However you won’t be able to use Rock Smash outside of battle until you’ve obtained the Dynamo Badge from Wattson, the 3rd Gym Leader.
HM06 Rock Smash Location
To get HM06 Rock Smash, you need to have two badges, and you should already have dealt with Team Aqua/Magma in Slateport City first. If you’ve done those things, you can head north and explore Route 110, where your rival will challenge you to a battle.
Continue heading north of Route 110 from Slateport City, and you’ll be able to reach Mauville City eventually.
Once you get into the city, here’s how to get to the Mauville Gym:
Step 1: Enter Mauville City’s south entrance.
Step 2: Head outside to Square Tower.
Step 3: Head back inside using the north entrance.
Step 4: Turn left, and Wally and his uncle should be standing outside.
When you reach the Gym, Wally will challenge you to a quick battle. After the battle, his uncle will give you HM06 as thanks for helping Wally catch his first Pokémon.
Using Rock Smash Outside of Combat
Simply put, HM06 Rock Smash is a bad move in battle. Arguably one of the worst HMs in the game. It’s a fighting-type move with a low base power of 40 and a defense-lowering effect that only works half the time.
I’d suggest giving this move to an HM Slave like Linoone if you’re not going to use it in battle.
Outside of combat, it’s a bit more practical.
North of Route 111, you’ll need to break through some rocks to pass through. Though you’ll have to beat Mauville’s Gym Leader first to be able to use it.
When breaking rocks, Pokémon and items may appear. The rocks respawn when you enter and exit the area so you can try to find whatever Pokémon or item you’re looking for.
Here’s a list of Pokémon you can find within these rocks:
And here’s a list of all obtainable items you could get when breaking rocks in Hoenn:
- Big Pearl
- Hard Stone
- Heart Scale
- Max Ether
- Max Revive
- Normal Gem
- Soft Sand
- Star Piece
In Mirage Spots, you can also find various fossils when breaking rocks depending on the version you’re playing:
|Omega Ruby||Alpha Sapphire|
|Armor Fossil (Shieldon)||Cover Fossil (Tirtouga)|
|Dome Fossil (Kabuto)||Helix Fossil (Omanyte)|
|Plume Fossil (Archen)||Skull Fossil (Cranidos)|
|Old Amber (Aerodactyl)||Old Amber (Aerodactyl)|