You get the hm strength and give it to one of your pokemon
Chat with our AI personalities
First, you have to get the HM strength, then teach it to and a Pokemon and you can move boulders.
Strength
You have to use a HM called strengh.
To move boulders in Pokemon Gold you need a Pokemon with the HM move Strength. Selecting the Pokemon in the menu outside of battle should let you use it if you have beaten the Olivine City Gym.
Use the HM move Strength.