Using Rock Smash move, break the rocks inside Rusturf Tunnel and the guy there will give you HM Strength.
If you have beaten Mauville Gym and have gotten HM ROCK SMASH, go to RUSTURF TUNNEL and clear out the rocks. The digger will grant you HM STRENGTH.
strength after the chamber
H.M
by using the hm strength
you get hm strength and hm defog after defeating two gym leader.Fantina(defog) Byron(strength).
by wining a certain gym battle
You get it from Steven in Mossdeep city.
the hm move strength is found in the cave Rusturf tunnel
You get it in Mossdeep City. Hope I helped :)
In Mossdeep City, Steven will give it to you.
you burn the game.
The way you get waterfall is by trading the waterfall HM from Fire Red Version or the other Version that have waterfall HM ( you can trade with a link cable or wireless adaptor)