Pokemon Battling is one of the biggest sports in Grennia, yet it has no national league. Instead it is handled by Pokemon Leagues International
(PLI), headquartered in Tokyo, Japan.

A trainer must be at least 16 to compete in professional Pokemon leagues, and defeat all eight gyms in their country.

Trainers may also travel and compete in other Pokemon Gyms and Leagues in different countries, provided their Pokemon's levels are temporarily reset or
put into a PC.

The Grennian gyms are located in the following locations:
Cannhill, Gekogashira City- Rock
Nest Peak, Gekogashira City- Bug
Commongarden, Gekkouga City- Dragon
Ascot, Gekkouga City- Steel
Arlington Heights, Gekkouga City- Normal
Pebble Beach, Keromatsu City- Water
Centrepoint, Keromatsu City- Fairy
Granwood, Satogeko City- Grass

Once all eight gyms are defeated, the trainer then progresses to the annual Grennian Pokemon League Conference.

If they progress into the final eight in the Conference, they are eligible to compete in the Grennian Elite Pokemon Conference,
which is only held on odd-numbered years.

If they secure a place in the final eight in the Elite Conference, they are eligible to compete with other
trainers from around the world in the Summer Olympics.

Extra note: Pokemon games, trading cards, etc do exist but they're more seen as Pokemon simulators or collectibles.