The way to get HM-6 (which is Rock Smash) in Pokemon Emerald is by going to Mauville City. When you get to Mauville City, proceed to a house in the immediate southeast of the city. Inside there will be a professor type of man who will hand over the HM-6 because he thinks you can handle it.
Head to One Island and go north using Surf keep going until you find a cave go inside then find an old man standing in the corner he gives you HM6.
Near the start of the game at Seanport City, walk into almost every house and find a guy with glasses, talk to him and he will present you HM06, Rock Smash.
Pokemon fire red how to have more Pokemon more than 6 Pokemon
cut, (if you've memorized everything and/or aren't lazy you don't need flash), surf, (fly is useful), rock smash, strength, and I think there's one more. but you don't really need fly or flash; you do need the others. hm 1 cut hm 2 fly hm 3 surf hm 4 strength hm 5 flash hm 6 rock smash hm 7 waterfall
Saffron- Sabrina
Waterfall pond on floors 6 thru 12 the hm Waterfall is needed to enter the dungeon
After you defete the Eliete 4 you can get to islands 4, 5 , and 6
HM 2 (fly) is in route 16HM 6 (rock smash) is in island 1
HM 6 rock smash is located on island 1. Use the seagallop ferry and when you get there, go to the ember spa. Then talk to the old man between the waterfalls and he will give you HM 6
Defog did not become a move until Generation 6 so you will not be able to find it in LeafGreen
Pokemon fire red how to have more Pokemon more than 6 Pokemon
Go to one island and find the ember spa there is an old man in there in a corner he has HM6
cut, (if you've memorized everything and/or aren't lazy you don't need flash), surf, (fly is useful), rock smash, strength, and I think there's one more. but you don't really need fly or flash; you do need the others. hm 1 cut hm 2 fly hm 3 surf hm 4 strength hm 5 flash hm 6 rock smash hm 7 waterfall
Vulpix on route 6 just beside Lavender Town.
you get H.M. 06 by going to island 1 and surfing up, after a while you will find more land . Keep going up until you see a cave, and talk to everyone in there. One person will give you H.M 06.
I'm pretty sure there are 7 HM's they are 1. Cut, 2. Fly, 3. Surf, 4. Strength, 5. Flash, 6. Rock Smash, 7. Waterfall
HM 1=Cut HM 2=Fly HM 3=Surf HM 4=Strength HM 5=Flash HM 6=Whirlpool HM 7=Waterfall
Saffron- Sabrina
HM#1. Cut HM#2. Fly HM#3. Surf HM#4. Strength HM#5. Defog HM#6. Rock Smash HM#7. Waterfall HM#8. Rock Climb