The Pokémon Presents showcase announced several games that will be set in the Sinnoh region, including full-fledged remakes of Pokémon Diamond and Pearl.
Pokémon series veterans can return Sinnoh region that they in The Legend of Zelda: Breath of the Wild. Pokémon Legends: Arceus is set in the ancient version of the Sinnoh region, where most of the landscape is still untamed, and wild Pokémon freely roam the countryside.
The official website for Shield era. The website features artwork of the Poké Balls used during the era of Pokémon Legends, and they're a little more basic than what modern trainers are accustomed to. These antique Poké Balls are made of wood and powered by steam, which puffs out of the top of the item when a Pokémon is caught. The design is so retro that they even have what resembles a pull tab on the front rather than the series' iconic white button.
The website only shows a single type of Poké Ball and it's unclear whether there will also be primitive versions of the other types of Poké Balls. It will be interesting to see if there is a steam-powered version of the Master Ball somewhere in the ancient version of the Sinnoh region, and it can be certain that the game will feature plenty more impressive low-tech items and architecture.
Pokémon prequels have long been speculated upon, so it's exciting to see how The Pokémon Company envisions the series' past in practice. While fans can continue to fantasize about a game starring a young Professor Oak exploring the Pokémon world and battling Agatha, Pokémon Legends: Arceus has finally answered the question of how trainers used to catch Pokémon in the days before Pokémon Red and Blue.
Pokémon Legends: Arceus will be available on Nintendo Switch in 2022.
Source: Pokémon Legends: Arceus