i assume you mean leafgreen. use cut on the door.
after falling through the first one go up, left, right, down.
You need to use Cut on the metal door
dotted hole is on the south side of six island. (the sapphire is in there) a little extra info: dotted hole does have braille in it.
Six island its a cave in the southern portion of the island.
The sapphire is on Six Island. You need a Pokemon to use cut on the dotted door of the cave.
cut the door
Stand in front of the door and have a pokemon use the HM move CUT. The door will break and you are able to enter the cave.
Use 'CUT' on the door.
How to get to lost cave in leaf green??
ITs at the bottom of island six in a place called dotted hole
well.......
With the dotted holes in leaf green, that is where you get one of the gems to get inside the Rocket Warehouse. Just have a Pokemon that knows cut, go up to it, then press START, POKEMON, ???, CUT. It's that easy!