there's a key in the pokemon mansion, that you'll need to unlock te gym's door.
after that, just use the quiz blocks next to the trainers to get to blaine.
The 7th gym leader in Pokemon yellow is in Cinnebar Island, which is south of Pallet Town. You need a Pokemon with Surf to get there.
Beat the first 7 gym leaders then go to the closed gym in Viridian and it will be opened.
Conquer the other seven Gyms, and then you will be able to battle the Viridian Gym. Its specialty is Ground-Type Pokémon.
You get it by beating Giovanni at the Viridian City gym, which you can't do until you have the other 7 badges.
The Only Way To Get Into The Gym In Viridian City Is You Have To Beat All 7 Of The Other Gym Leaders Along With Beating The Leader Of Team Rocket.....As Long As You Have Strong, High Level Pokemon You Can Beat Him...Hint The Leader Of This Gym Is Also The Leader Of Team Rocket Giovanni.....
in the last gym battle.the one that was locked opens when you have 7 badges.
go to cinnabar island then go into Pokemon mansion go through here to get the secret key which opens the 7th gym.
To get the final badge in Pokemon yellow, simply have all 7 other badges, (You also must have beaten Giovanni at both the Game Corner and Silph Co.) and go back to Viridian City, the Gym will now be open. Find your way through the maze and go to the Gym Leader, It's Giovanni from Team Rocket! His Pokemon are Dugtrio, Persian, Nidoqueen, Nidoking, and Rhydon. Good luck!
Pokemon ruby where is the 6 gym
Get 7 gym badges, go to spear pillar, get through distortion world
After u beat the first 7 u will go back to pallet town and then go to viridian and the gym that was earlier locked is now open (Giovanni is the boss)
There are 9 tiles in the Saffron Gym. 7 of them contain Gym Trainers. The other 2 are Sabrina and the entrance. Sabrina is in the middle. To reach her, it's like this long hard maze.