Pokémon Sun and Moon are the first mainline Pokémon games since Pokémon X and Y, which launched on Nintendo 3DS in 2013. These were followed by Pokémon Omega Ruby and Pokémon Alpha Sapphire, which were 3DS remakes of 2003's Pokémon Ruby and Pokémon Sapphire on Game Boy Advance. 

Following in the tradition of previous games in the Pokémon series, players choose one of three special Pokémon to be their first partner. These are among the first Pokémon players will encounter in the game. In Pokémon Sun and Pokémon Moon, players will be able to choose between the newly discovered Grass- and Flying-type Pokémon Rowlet, Fire-type Litten, and Water-type Popplio. 

For a Pokémon Trainer, knowing the Pokémon types and how they match up against one another in battle is vital. Grass-type Pokémon are strong against Water types, but weak against Fire types. Fire-type Pokémon are strong against Grass types and weak against Water types. And Water-type Pokémon are strong against Fire types, but weak against Grass types.