you go to blackthorne city and challenge the 8th gym there
beat pryce
beat the 8th gym
first you have to beat team rocket in goldenrod city then go to mahogany town and that guy lets you pass him and that's all I know.Good luck! Go to Mahogany Town, beat Team Rocket there, and then you can get to the seventh gym leader.
the 7th gym in Johto is in Mahogany town. And in Kanto the seafoam islands.
beat gym leader
beat blue to get it.
go and beat the 8th gym
The eighth gym leader still awaits, as well as the whole of Kanto.
Simply beat the gym leader in every gym.
Beat all the team rockets and then the gym is open!!!
Go to the third
Beat 16 Gym Leaders.