The clauses below apply to all BW tiers except Challenge Cup, which has no clauses, and some for Ubers.
Species Clause - A player cannot have two Pokemon with the same
National Pokédex number on a team. For example, using a team with two
Koffing would break this clause. Using different formes on the same
team, such as Rotom-W and Rotom-C, also breaks the clause since they
share the same Pokédex number (#479). This rule was implemented for BW
tiers following a Policy Review vote on October 30, 2010. Sleep Clause
- You lose if, at the end of your turn, two of your opponent's Pokemon were put to sleep by a move you used but were not forced into, and
neither have had their sleep removed since then. The clause basically
means that if you have already put a Pokemon on your opponent's side
to sleep and it is still sleeping, you can't put another one to sleep.
A move you were "forced into" is a move you must use because all other
moves (that cannot inflict sleep) are disabled (by Choice item,
Encore, or some combination of Taunt, Disable, Torment, and lack of
PP) and you cannot switch (due to trapping moves, trapping abilities,
Ingrain, or having all other Pokemon be fainted). A move you used
includes moves called by Metronome, Sleep Talk, Assist, Me First, or
Copycat. It does not include Magic Coat or Magic Bounce. Rest, used by
either player, is never counted by this clause. The definition of this
rule was debated on in a Policy Review discussion. This rule was
implemented for BW tiers following a Policy Review vote on October 30,
2010. Evasion Clause - A Pokemon may not have the moves Double Team or Minimize in its moveset. Generally, this rule will be automatically
enforced in simulator play. In Wi-Fi play, a player is considered to
have broken the clause when a Pokemon is revealed to have been brought
into the battle with a banned move. This rule was implemented for BW
tiers following a Policy Review vote on October 30, 2010. This rule
does not apply to BW Ubers following a Policy Review vote on December
21, 2012. OHKO Clause - A Pokemon may not have the moves Fissure,
Guillotine, Horn Drill, or Sheer Cold in its moveset. Generally, this
rule will be automatically enforced in simulator play. In Wi-Fi play,
a player is considered to have broken the clause when a Pokemon is
revealed to have been brought into the battle with a banned move. This
rule was implemented for BW tiers following a Policy Review vote on
October 30, 2010. Moody Clause - A team cannot have a Pokemon with the
ability Moody. This rule was implemented for BW tiers by acclamation
on June 7, 2011. Banlists
Uber
Everything that is not covered by a metagame-wide clause is allowed in
the Uber tier. OU
Banned Pokemon - A team cannot have any of the Pokemon found in the
following tiers: Ubers. Banned Abilities - A team cannot have a
Pokemon with any of the following abilities: Sand Veil and Snow Cloak.
Drizzle + Swift Swim - Using both a Pokemon with Drizzle and a Pokemon
with Swift Swim on the same team is banned. UU
Banned Pokemon - A team cannot have any of the Pokemon found in the
following tiers: BL, OU, and Ubers. Banned Abilities - A team cannot
have a Pokemon with any of the following abilities: Drought, Sand
Stream, Sand Veil, and Snow Cloak. Drizzle + Swift Swim - Using both a
Pokemon with Drizzle and a Pokemon with Swift Swim on the same team is
banned. RU
Banned Pokemon - A team cannot have any of the Pokemon found in the
following tiers: BL2, UU, BL, OU, and Ubers. Banned Abilities - A team
cannot have a Pokemon with any of the following abilities: Drought,
Sand Stream, Sand Veil, and Snow Cloak. Shell Smash + Baton Pass -
Using a Pokemon carrying both Shell Smash and Baton Pass in its
moveset is banned. Drizzle + Swift Swim - Using both a Pokemon with
Drizzle and a Pokemon with Swift Swim on the same team is banned. NU
Banned Pokemon - A team cannot have any of the Pokemon found in the
following tiers: BL3, RU, BL2, UU, BL, OU, and Ubers. Banned Abilities
- A team cannot have a Pokemon with any of the following abilities: Drought, Sand Stream, Sand Veil, and Snow Cloak. Shell Smash + Baton
Pass - Using a Pokemon carrying both Shell Smash and Baton Pass in its
moveset is banned. Drizzle + Swift Swim - Using both a Pokemon with
Drizzle and a Pokemon with Swift Swim on the same team is banned.
Little Cup
The Little Cup rules are here. Little Cup is not a tier below NU;
rather, it is standalone entity. - Smogon rules and banlists.
