In Pokemon diamond how do you move the big boulders?

You can move boulders in Pokemon Diamond by using the move Rock Smash. This move can be learned by many Pokémon, including Onix, Geodude, and Nosepass. To use this move, select it from your Pokémon's moveset and then target a boulder. The boulder will then be broken and you will be able to walk past it.

To learn the Rock Smash move, one of the many options listed below may apply to your situation.

* Onix learns the move through level-up at level 26.

* Geodude learns the move through level-up at level 26.

* Nosepass learns the move through level-up at level 26.

* You can also get a TM that teaches Rock Smash from the department store in Veilstone City. Once there, head up the stairs to find a small room with two workers. The one on the right sells TMs. Get to the 3rd page of items being sold and make your purchase by spending 2,500.