Pokémon GO has hit the ground running in 2021, with events and updates already in effect on the app. One new feature, Collection Challenges, has already put players to the test in the Unova event, but another one will launch on Jan. 12 with the Sinnoh Celebration.

Collection Challenges are intended to help players collect Pokémon featured in various GO events, so different events will prompt different Collection Challenges. To see which Pokémon are part of a given challenge, players will need to choose the Today view during an event. Once an event ends, the Challenge will disappear with it, so players need to complete their collections before time runs out.

Related: Pokémon GO Artist Explains the Meaning of the New Loading Screen

As Pokémon GO players complete Collection Challenges, they will earn rewards to add to their new Elite Collector medal, which has been introduced specifically for this new feature.  featured in different in-game events, they will be able to earn rewards and add to the new Elite Collector medal.

In the Unova event, players need to catch Lillipup, Ferroseed, Roggenrola, Snivy, Tepig, Oshawott, Herdier, Solosis and Blitzle. For completing the Collection Challenge, players will earn Stardust, 25 PokéBalls and five Rare Candy. Rewards for the Sinnoh Celebration have not been revealed, but from Jan. 12 at 10 a.m. to Jan. 17 at 8 p.m. local time, players will want to focus on catching Turtwig, Piplup, Buizel, Purugly, Hippopotas, Snover, Skorupi, Bidoof, Cranidos, Combee, Shieldon, Drifloon, Glameow and Chimchar, which will appear more frequently in the wild. Players will also have a chance to encounter a Shiny Buizel.

Related: Pokémon GO: 7 Features and Improvements We Want in Future Updates

Pokémon GO Collection Challenges are interesting, because it doesn't matter which Pokémon a Trainer has caught before, or which ones they have evolved. Player level doesn't factor in, either. It is a completely even playing field for all Trainers to complete the challenge.

While players may have caught these Pokémon before, they will need to catch them again for Collection Challenges. This may not seem difficult, but it could prove harder than players expect.

To complete each list during its corresponding event, players will need to visit different areas and PokéStops, and make sure they have plenty of Golden Razz Berries, Silver Pinap Berries and Razz Berries at hand to catch them. Ultra Balls and Great Balls are good to have, as well. It may seem like overkill to use a Golden Razz Berry and an Ultra Ball on some of the Pokémon needed for a Collection Challenge, but it only takes one fleeing and staying elusive for a player to fail to complete the challenge, which is wildly frustrating.

Ultimately, Collection Challenges don't leave room for players to be picky about which Pokémon they catch. They need the entire list to earn the rewards, in the allotted time frame.

KEEP READING: Ditto Reproduction May Have Disturbing Implications for Pokémon Breeding