I think it has something to do with braille. And the move dig. If I'm not correct, look it up on YouTube.
I don't think you can get regirock in pokemon ruby.
Read the braille then do the following: Step right twice then step down twice then use rock smash the door should open.
It's different in different versions.
The braille inside the cave says this: Run around the room. Stay close to the walls. Good Luck.
read sign, wait two minutes the door will open
Regirock is at the bitten if the desert on route 111. You need to have already opened the outside door by going to the cave after pacifidlog town. Take a relincanth and a wailord. Put the relincanth first and the wailord last in your party. Go in, using dig, then go to the back room and talk to the center of the wall that has Braille. Go to regirocks cave when it is open, then go in. Walk to the Braille at the top of the cave. Read it, then take two steps left and two steps down. Then use rock smash. If you do exactly that, a door will open where the Braille was. Walk in and regirock will be there.
In order to get Regirock's tomb to open, you have to go into the cave, read the Braille description and then go 2 steps left, 2 steps down and then use Rock Smash.
you get the sapphire stone in the 6th island you have to open the cave somehow and you get a lugia if you go to the very bottom use cut on the cave
You must has a pokemon had a Rock Smash.You go to Desert Ruins and go to a cave does open when you go to Pacificlog and go to a some earthquake and go again there the cave is open,Go enter, Read the text Go down 2 and go right 2 ,...
go to the desert, go way down to the bottom of the desert, go in the cave, go straight up to the writing press "a" then go right twice and go down twice, then use strenght and the door will open.
A cave is a hollow rock really. The interior of a cave is dark and moist. A cave is a big hollow rock really. :D
sorry but you can't find it in Pokemon diamond/pearl without migrating regirock from Pokemon ruby, sapphire, or emerald. But I think there is a cheat on the action replay for it, but I don't know the cheat.