Tiers are an attempt by players to classify Pokémon in a given generation by their utility 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 by Smogon and Pokémon Online and published on their respective websites. 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.
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" tiers ("BL", "BL2", and so on). Pokémon in a borderline tier are "too strong" for one tier, but not sufficiently used in the next higher tier to be a part of it. In essence, borderline tiers serve as a ban list for a lower tier.
Below are six of the most common tiers.
The Uber tier is effectively a banlist for the OU tier, as "standard" battles include everything in the OU list and below. Pokémon in the Uber tier were deemed too powerful or destabilizing to the OU metagame to allow. Ubers, if allowed, cause extreme "centralization" of strategies—in other words, it is impossible or very difficult to counter them in a reasonable manner.
The Uber tier may include any Pokémon, not necessarily just Legendary Pokémon. Typically, it includes all 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 the tier. 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.
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. 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. If an OU Pokémon is not used enough in the OU tier, it will fall to the UU tier.
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 commonly 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/LU tier.
RarelyUsed/LittleUsed, commonly referred to as either "RU" or "LU". While the name of the tier varies, its "level" is equivalent. 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/LU Pokémon is not used enough in the RU/LU 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/LU. 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 and/or have lackluster stat distribution. Unlike the other tiers, PU is not an acronym, but simply denotes Pokémon that are below NU standards in terms of usage and viability.
The Pokémon in this tier are so atrocious that they are completely unviable in any tier. This is the lowest possible grade a Pokémon can receive in competitive play.
Not Fully Evolved
This group is more commonly known as "NFE", and as the name implies, contains most Pokémon that have not yet reached their final evolution stage and do not have a high enough usage to appear in any tier. This group is not actually a tier, but rather a collection of Pokémon without significant usage even in the lowest tier.
Some Pokémon are listed in tiers but are sometimes used in competitive play outside of their own tier because they have a change during evolution that modified their disposition enough to allow them to stay competitive, even some in an unevolved state.
- Porygon2, which is due to its evolution, Porygon-Z, having lower Defense and Special Defense, meaning Porygon2 can be used as a wall, unlike its evolution.
- Pikachu holding Light Ball can have higher Attack and Special Attack than its evolution, Raichu.
- Magneton, as previously stated, is still used in lower tiers because it carries the ability to trap Steel types with Magnet Pull. It also has use in OU battles, as its slightly higher speed than Magnezone allows it to outspeed many OU Pokémon that Magnezone cannot.
- Eviolite, an item that multiplies both Defense and Special Defense of not-fully-evolved Pokémon by 1.5, has increased the popularity of several other pre-evolutions, such as Gligar, Dusclops, and Chansey, among others, Dusclops and Chansey even being in a higher tier than their evolutions, Dusknoir and Blissey, respectively, on some tier lists.
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 too powerful 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%.