[description]
Composition
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OU (OverUsed) is Smogon's fundamental usage-based tier. With the exception of Pokémon banished to the Uber tier, every Pokémon can be used in OU, including Pokémon from UU, RU, NU, and PU. While all non-Uber Pokémon can be used in OU, only those Pokémon that make up at least ~3.41% of total weighted usage in the tier are designated 'OU.' A Pokémon is truly 'OU' if a typical competitive player is more than 50% likely to encounter that Pokemon at least once in a given day of playing (20 battles).

Tiering
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Smogon's OU tiering is ruled by [a council of five high-level players](http://www.smogon.com/forums/threads/meet-the-overused-tiering-council.3598286). The purpose of this thread is to introduce the OU senators to the public and to explain how they handle the tiering process for the OU tier in Pokemon Sun and Moon.

Play Restrictions
=================

Players cannot use Pokémon from the [Uber tier](/dex/sm/tags/uber).

Players must abide by the following clauses:
* [Smogon-wide Clauses](http://www.smogon.com/sm/articles/clauses).

Players cannot use the following abilities:
* (ability: sm/Arena Trap)
* (ability: sm/Power Construct)
* (ability: sm/Shadow Tag)

Players cannot use the following moves:
* (move: sm/Baton Pass)

The OU Forum
================

Learn
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The [Simple Questions, Simple Answers](http://www.smogon.com/forums/threads/simple-questions-simple-answers-thread-read-the-op-before-posting-a-thread.3587186/) thread is a great place to ask any simple questions you might have relating to the OU metagame. Do not make new threads for questions that could be answered here.

The [USM OU Analyses](http://www.smogon.com/forums/forums/ou-analyses.406/) forum is the place to go for writing analyses to be uploaded to the official Smogon Dex. You may reserve an analysis in the [Index](https://www.smogon.com/forums/threads/ultra-sun-moon-ou-reservation-index-read-first-three-posts-before-posting.3621432/) or comment on analyses that are a WIP.

Participate
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The [USM OU Viability Rankings](https://www.smogon.com/forums/threads/usum-ou-ultra-viability-ranking-thread.3621329/) shows how well every OU-viable Pokémon fares in the OU tier.

The [USM OU Metagame Discussion](http://www.smogon.com/forums/threads/usum-metagame-discussion.3621042/) thread allows players to discuss current trends in the OU metagame.

The [USM OU Teambuilding Competition](http://www.smogon.com/forums/threads/usm-ou-teambuilding-competition-v3-round-22-volcarona-voting-phase.3623860/) gives a core or idea for members to build the best possible teams in order to win in a community vote.

You can help contribute to Smogon's social media pages by writing [USM OU Pokemon Spotlights](http://www.smogon.com/forums/forums/facebook-spotlights.450/) for the [Facebook](http://facebook.com/smogonu) and [Twitter](http://twitter.com/smogonu) pages.

Resources
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The [SM Battle Mechanics Research](http://www.smogon.com/forums/threads/pokemon-sun-moon-battle-mechanics-research.3586701/) thread is the prime hub for learning about all of the mechanics changes from Generation 6 to Generation 7.

The [USM OU Good Cores](https://www.smogon.com/forums/threads/sm-ou-ultra-cores-v2.3639111/) thread is a compendium of the strongest/most resilent cores in the current metagame.

The [USM OU Speed Tiers](http://www.smogon.com/forums/threads/sm-ou-speed-tiers.3587531/) thread offers useful information regarding how the speeds of threats in the SM OU metagame compare.