X/Y UnderUsed Metagame Primer

Composition

UU (UnderUsed) is Smogon's second usage-based tier. All Pokémon that are not OU by usage and are not banned to Ubers or UUBL can be used in UU, including Pokémon from RU, NU, and PU. While any of the aforementioned Pokémon can be used in UU, only those Pokémon that make up at least ~3.41% of total weighted usage in the tier are designated 'UU.' A Pokémon is truly 'UU' if a typical competitive player is more than 50% likely to encounter that Pokémon at least once in a given day of playing (20 battles).

A list of the current UU Pokémon and those with UU analyses for the XY era are found on the dex page.

Play Restrictions

Players cannot use Pokémon from the Uber tier, OU, or UUBL.

Players must abide by the following clauses:

Players cannot use the following abilities:

Players cannot use the following moves:

The UU Forum

Learn

The UU Simple Questions, Simple Answers thread is a great place to ask any simple questions you might have relating to the UU metagame. Do not make new threads for questions that could be answered here.

The UU Analyses forum is the place to go for writing analyses. You may reserve an analysis in the Analysis Reservation Thread or comment on analyses that are a WIP.

np: ORAS UU Stage 6 - Slow Hands is the place to go to learn about and discuss the metagame.

Better Battlers Project: UU is a project where experienced UU players showcase battles from other players and provide commentary for newer players to learn about the metagame and how to battle.

Participate

The UU Viability Rankings shows how well every UU-viable Pokémon fares in the UU tier.

The Next Best Thing project takes a look at a different Pokémon each week in an attempt to find new and creative sets for it.

The UU Teambuilding Compendium project aims to build an effective team for the UU metagame through community submissions and voting.

#XYUU is the official IRC channel of UU and is a great place to interact with other players in real time.

Battle of the Week: UU Edition is a project where community members vote on players they want to see battle.

The Iron Chef: Smogon UU Edition is a challenge to build a team around a certain concept and face off against other successful players.