Ahead of Game Informer's November cover story on Pokemon Sword and Shield, The Pokemon Company is clarifying a detail about the number of gyms in the game that made it seem like there'd be 18 gyms to challenge for badges in the Galar region. Instead, both Sword and Shield will have the standard "eight Gyms and eight Gym Leaders that Trainers can battle for a traditional Gym Challenge experience."
The confusion may have arisen through the Japanese-to-English translation of a quote by Game Freak's Shigeru Ohmori. Ohmori, the director of Pokemon Sword and Shield, told Game Informer that in "the background to the story" there are 18 Galar gyms—one for each Pokemon type—that are divided into Major and Minor Leagues. The eight gyms you'll challenge for badges in Sword and Shield are their respective version's Major League gyms.
This is the fictional justification for why Pokemon Shield features the exclusive Ghost-type gym leader Allister while Sword features Fighting-type expert Bea. In Sword's story, the Fighting gym is advanced enough to be in the Major League but it failed to qualify in Shield, and vice-versa with the Ghost gym.
"Over the course of the main story, Trainers will challenge eight Gyms, which are all in the Major League," confirms The Pokemon Company's clarifying statement. The statement goes on to emphasize that Sword and Shield follow a "traditional" eight-gym progression:
"Which Gyms appear in the Major League and Minor League will differ between Pokémon Sword and Pokémon Shield. For example, depending on the version of the game, Trainers will be able to challenge different Gym Leaders, such as Bea or Allister.
Each version will have eight Gyms and eight Gym Leaders that Trainers can battle for a traditional Gym Challenge experience that fans have enjoyed throughout the Pokémon video game series."
The question the statement raises and then doesn't answer is whether any Minor League gyms will actually appear in Pokemon Sword and Shield. All we know for certain is that we'll be challenging eight gyms for badges, and the Minor League gyms are explicitly not part of that progression. Basically, you probably shouldn't go into Sword and Shield expecting something like Pokemon's Gen 2 heyday of eight Johto and eight Kanto gyms to challenge in a single game.
Keep up to date with all things Pokemon Sword and Shield in our need-to-know guide.