How To Unlock Pewter City Gym

Unlike previous Mainstream Pokemon Games, every Pokemon Gym found within this game have certain requirements that must be met before your trainer will be allowed to challenge said Gym. The first Pokemon Gym within the Kanto Region is found in Pewter City. This Pokemon Gym is full of trainers that have a specialty with Rock Type Pokemon, and because of this, your trainer will be required to have at least one Grass Type or Water Type Pokemon in their Party in order to gain access to the Gym. (It will not be required to use said Grass Type or Water Type when in battle, but it would probably be a good idea since Rock Type Pokemon are weak to both of these types of Pokemon.)