I can't consider what route but if you look at your trainers case, then it says you have to go ti Pastoria. There are two different routes I believe to get there.
I believe it is the gym in Sunnyshore city, or something like that. Actually it is Veilstone :)
Go to the lake south of Veilstone City.
After beating the third Gym Leader (Maylene the Veilstone Gym Leader) in Pokémon Diamond, you then head to Pastoria City to battle the Gym Leader there who is named Crasher Wake.
You have to beat the Veilstone Gym first.
you beat the gym leader then you battle those 2 guys with dawn if your a boy or lucas if your a girl and when you beat them they drop the key that's what i think if that doesnt work don't blame me
You have to beat(or Catch) Dialga first.
veilstone city after u beat the 7th gym and went to lake acuity
I believe it is the gym in Sunnyshore city, or something like that. Actually it is Veilstone :)
Alright. You get it in Veilstone City in the Team Galactic HQ and Cyrus will give it to you after you beat him. Use it carefully you only get one unless you have a diamond cheat for it.
The boss of Team Galactic (Cyrus) gives you the Master Ball after you beat him in the Team Galactic hideout in Veilstone City. This happens after you beat Candice in the Snowpoint City Gym (7th Gym).
um the galactic boss will give it to you after you beat him in the veilstone building
Go to the lake south of Veilstone City.
After you beat the elite 4 go to Veilstone city. when your there go to all the moon rocks.talk to the karate guy right before route 209
From Cyrus after you beat him at the Galactic Veilstone Building (4th Floor)
After beating the third Gym Leader (Maylene the Veilstone Gym Leader) in Pokémon Diamond, you then head to Pastoria City to battle the Gym Leader there who is named Crasher Wake.
Cyrus gives it to you after you beat him at the warehouse in Veilstone city.
You have to beat the Veilstone Gym first.