beat the gym leader
You have to go to Silph Co in Pokemon LeafGreen. You have to go there to get the Silph scope, which you need to advance.
On the 5th floor of silph co.
7th floor.
Saffron City.
Save Silph Co., Just like in Blue.
You can only get one masterball.the owner of silph co gives it to you.
Defeat Giovanni In The Sliph Co. And It Is Gonna Be Unlocked.
In Silph Co. in Saffron city. After you get to the top of the building.
Somebody will give it to you at the Silph Co. in Saffron city.
Help silph co then talk to the president he gives the masterball to you.
saffron citysilf is actually spelled silph co.
you get it in silph co which is in saffron city. after the boss fight, the leader of silph co gives you one.