Go to mahogany town then to route 44 into the ice to Blackthorn City. It worked for me.
You have to go through Diglett's Cave.
blackthorn
You have to navigate through the ice cave
Its right behind blackthorn city
Yes.
blackthorn city
After mahogony town befor blackthorn
To Blackthorn City.
you just go south of blackthorn city
in the dark cave near blackthorn city
It is at he way to blackthorn city
Blackthorn city, (east of mahogany town).