From Bulbapedia, the community-driven Pokémon encyclopedia.
Tiers are an attempt by players to classify Pokémon in a given generation by their utility in competitive battles. They can be found in any game with variable characters, including Pokémon and Super Smash Bros. The classification of Pokémon into tiers can be challenging, as a Pokémon's stats or moves are not the only factor which can impact a match. Combinations of Pokémon, along with player skill and overall strategy, may affect the outcome.
Tiers in Pokémon
Pokémon features hundreds of species available for use in a battle, with great variation in in base stats, movesets, Natures, and Abilities. There are multiple tiers, of which the six most common are listed below. Individual sites, users, or organizations may publish tiers. The most prominent organizations are Smogon and Pokémon Online. They publish tiers on their websites for each generation; tiers are updated on a regular basis to reflect the current competitive battling environment.
Tier lists are often targets of discussion because there is no "official" tier list for Pokémon and as strategies evolve Pokémon may move from one tier to another. However, official tournaments will present "ban 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, nothing in a tier above UU (BL, OU, or Uber) may be used, but things in lower tiers (such as RU or NU) are allowed.
The Uber tier is effectively a banlist for the OU tier (described below), as "standard" battles include everything in the OU list and below. Pokémon in the Uber tier are deemed too powerful or destabilizing to the metagame to allow. Ubers, if allowed, would cause a too-substantial "centralization" of strategies to those who create the tiers.
The Uber tier may include any Pokémon, not just legendary Pokémon. Not all legendary Pokémon are Uber, however; most members of the various non-mascot legendary trios are allowed in OU play, and even Black Kyurem is allowed in standard play (despite being restricted in-game) due to various flaws preventing it from becoming too centralizing.
Over-Used, commonly abbreviated as "OU", refers to Pokémon that are most frequently used in standard play.
Being designated OU does not have to do with a Pokémon's "power" or "ability". OU, as with all tiers, is defined based on usage. It may change by generation or even within a generation. For instance, Magneton was considered an OU Pokémon in Generation III solely because it was used as a counter for Skarmory, another commonly used Pokémon. In Generation IV Magnezone, the evolution of Magneton, took over its place in OU, due to increased stats and a broader movepool. Smogon moved Blaziken from Borderline to Underused to Uber in Generations III through V, skipping designation in the Overused tier entirely.
Pokémon in Borderline, commonly referred to as "BL", are considered by some to be too strong for Under-Used, but are not sufficiently used in competitive battles to be deemed "overused." In effect BL serves a ban list for Under-Used.
Under-Used, commonly referred to as "UU", designates Pokémon whose use is limited as they are not competitive in OU competition. Pokémon classified as Under-Used are often outclassed in stats, available moves, abilities, or a combination of those by Pokémon in higher tiers. For example, in Generation V Machamp is designated as "UU" because to Conkeldurr having Mach Punch and better bulk. UU Pokémon can be, and are, used in OU battles, but are usually underpowered here.
Pokémon in Borderline 2, or "BL2", as it is more commonly known, are considered to be too powerful for the RU/LU tier but are not competitive in UU. As such, it serves as a banlist of the RU/LU tier.
This tier is referred to as either "RU" or "LU". While the name of the tier varies, its "level" is equivalent. It serves to designate Pokémon who are not used commonly used in the Under-Used (or higher) tiers. For example, Nidoqueen in Generation V is considered RU because it is rarely used in UU battles.
Never-Used, commonly referred to as "NU", is for Pokémon who are not frequently used in the RU/LU tier. The name is not literal, but reflects the extremely limited utility the Pokémon in the tier. Most novelty Pokémon reside in this tier. Some Pokémon that are pre-evolutions of Pokémon that are in the OU or Uber tier may be classified as NU. Many NU Pokémon are common in Pokémon Contests and Pokémon Super Contests.
Not Fully Evolved
This tier is more commonly known as "NFE", and as the name implies, contains most Pokémon that have not yet reached its final evolution stage.
- Main article: Little Cup
Little Cup is where the weakest Pokémon, (frequently lowest evolutions), are allowed. Examples include Pokémon like Bulbasaur and Timburr. Pokémon that do not evolve at all, such as Luvdisc, are generally not allowed in the tier, and some unevolved Pokémon are deemed too powerful for Little Cup and therefore banned. In Generation V, Too-powerful Pokémon that have not yet evolved include Gligar, Carvanha, and Meditite among others. It follows the same rules as the Pokémon Colosseum and Pokémon Communication Club Colosseum special rule.
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, while its evolution can not.
- Light Ball holding Pikachu are also due to the Light Ball doubling Pikachu's Attack and Special Attack stats, as well as Pikachu being a very common fan favorite.
- Magneton, as previously stated, is still used in lower tiers because it still carries the ability to trap Steel types with Magnet Pull. It is also used because of its various resistances and high Special Attack. It also has some 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 defenses of Not Fully Evolved Pokémon by 1.5, has made several other pre-evolutions—such as Gligar, Dusclops, Porygon2 and Chansey—popular in higher tiers, Dusclops even being in higher tiers than its evolution on some tier lists.