From Bulbapedia, the community-driven Pokémon encyclopedia.
Tiers are an attempt by players to classify Pokémon in a given generation by their utility or popularity in competitive battles. The classification of Pokémon into tiers can be challenging, as a Pokémon's statistics or moves are not the only factors that can impact a match. Combinations of Pokémon, along with player skill and overall strategy greatly affects the outcome.
Tiers in Pokémon
Pokémon features hundreds of species available for use in a battle, with great variation in base stats, movesets, Types, and Abilities. Individual sites, users, or organizations may publish tiers, but the most prominent tier lists are produced and published by Smogon and Pokémon Online and usually based on statistics from Pokémon Showdown. Tiers for current metagames are updated on a regular basis to reflect the current competitive battling environment; older generations tend to retain the same banlists. Pokémon do not necessarily have high statistics to be in high tiers. For example, Pelipper is usually tiered much higher than Slaking because of their abilities, despite Slaking's stronger stats.
Tier lists are often targets of discussion because there is no "official" tier list for Pokémon. Tiers are often quite fluid—as strategies evolve, Pokémon may move from one tier to another. However, even official tournaments will present lists of disallowed Pokémon.
As commonly defined, a "standard" battle allows any Pokémon not listed in the Uber tier. Tiers are exclusive in only one direction; for instance, in a UU battle, Pokémon from tiers above UU (OU or Uber) are banned, but Pokémon from lower tiers (such as RU or NU) are allowed.
A common addition to the tiers below may be several "Borderline" or "Banlist" tiers ("UUBL", "RUBL", and so on). Players can vote Pokémon into a borderline if said Pokémon are "broken" for one tier, but not sufficiently used in the next tier to be a part of it. Pokémon are banned usually because they are very difficult to counter without specifically preparing for them. In other words, battles involving "broken" Pokémon are more likely to be decided by team matchups and the presence of specialized counters rather than "player skill".
Below are six of the most common tiers.
The Ubers tier is effectively a banlist for the OU tier, as "standard" battles allow everything in the OU list and below. Players can, similarly to BL tiers, vote to ban Pokémon to Ubers if said Pokémon are too "broken" to the OU metagame to allow.
The Uber tier may include any Pokémon, not necessarily just Legendary Pokémon. Typically, it includes most Legendary game mascots except Black Kyurem, due to various factors preventing it from becoming "too centralizing". Although many legendary Pokémon reside in the Uber tier, a far larger number exists in lower tiers due to similar inadequacies.
After the release of Pokémon Omega Ruby and Alpha Sapphire, due to the dominance of Mega Rayquaza, Smogon made their version of Ubers a full-fledged tier, allowing bans from Ubers. Smogon has also banned the move Baton Pass from their version of Ubers. However, unlike other tiers, it is not affected by usage. As a result, Smogon also endorses a playstyle referred to as "Anything Goes", which has no fan-imposed rules other than the "Endless Battle Clause".
OverUsed, commonly abbreviated as "OU", refers to Pokémon that are most frequently used in standard play. Pokémon in this tier are often Legendary or Mythical and almost always fully evolved.
OU status does not have to do with a Pokémon's power or ability. The Pokémon that make up OU, as with all tiers, are determined based on usage. If an OU Pokémon is not used enough in the OU tier, it will fall to the UU tier, and "not used enough" usually means that a player can play 20 battles and have less than a one-half chance of encountering an opponent using said Pokémon. (i.e. appears on less than approximately 3.4% of teams) A Pokémon's tier may change from generation to generation. For instance, Magneton is often considered OU in Generation III because of its advantage over Skarmory, another commonly used Pokémon. In Generation IV, Magnezone, the evolution of Magneton, took Magneton's role in OU in some tier lists due to its generally higher base stats.
UnderUsed, commonly referred to as "UU", consists of Pokémon that are not used enough to be in OU. Pokémon classified as UU are often outclassed by Pokémon in higher tiers, possibly as a result of generally lower base stats, available moves, or Abilities. For example, in Generation V, Machamp fell to UU in some tier lists largely as a result of the introduction of Conkeldurr, which has Mach Punch, Drain Punch, and generally superior base stats. UU Pokémon are sometimes used in OU battles, but most have smaller niches. If a UU Pokémon is not used enough in the UU tier, it will fall to the RU tier.
RarelyUsed, commonly referred to as either "RU". The tier consists of Pokémon that are not used enough to be in UU. For example, Escavalier is considered RU in Generation V in some tier lists because it is not used enough in UU battles. If an RU Pokémon is not used enough in the RU tier, it will fall to the NU tier.
NeverUsed, commonly referred to as "NU", consists of Pokémon that are not used enough to be in RU. The name is not literal, stemming from the tiers of Generation I, where Neverused Pokémon had generally lower "competitive value" in comparison to other Pokémon. Some Pokémon that are pre-evolutions of Pokémon in higher tiers may be classified as NU.
PU consists of Pokémon that are not used enough in NU. Some Pokémon in PU are not fully evolved or have lackluster stat distribution. Unlike the other tiers, PU is not an acronym, coming from the expression of disgust "PU".
Untiered is a list of all Pokémon that are not used enough in PU and is not a playable tier. Generally, the use of Untiered Pokémon in a competitive metagame is strongly discouraged.
Tiers in special formats
- Main article: Little Cup
Little Cup is an entirely separate battle style where only the Pokémon that are the lowest evolutionary stage in their family are allowed, like Bulbasaur and Mienfoo. Pokémon that do not evolve at all, such as Luvdisc, are not allowed in the tier. The moves Sonic Boom and Dragon Rage are also prohibited. All Pokémon must be level 5 or lower to compete.
This format is based on the Stadium Cup.
Some unevolved Pokémon—for example, Meditite, Scyther and Gligar—are sometimes considered broken and banned in some tier lists. In this special battle style, Berry Juice is also sometimes banned.
Eviolite is one of the most commonly used items in this format, because it can boost the Defense and Special Defense of any legal Pokémon in this format by 50%.