Where do you rock smash in Pokemon LeafGreen?

Answer 1

you get it in ember spar on kindle road near one island when you try to get moltres,

enter the hot springs and talk to the man in between the two water falls at the back and get it. (directions to get it) 16 up, 8 right, 12 up, 11 left, 2 up

NOTE: Start at One Island
Kindle Road's Spa.
From old man in Ember Spa, on Kindle Road, on the 1st Sevii Island.
on the route next to mt. ember there is a cave and an old man will give you it.
After you get the secret key at cinnabar island,go beat blaine,the 7th gym leader.Then,when you come out of the gym bill will appear and will take you to one island.Bills friend will give you a tri pass.Go to ember spa(just north of where you are)and talk to the old man.there,he will give you the hm for rock smash.
The HM06 which contains Rock Smash is given by an old man on One Island in the ember spa.