One-hit knockout move

One-hit knockout moves (Japanese: わざ one-hit knockout move), commonly abbreviated as one-hit KO moves or OHKO moves, are moves that cause the target to immediately faint, regardless of its current HP. To make up for this, they have particularly low accuracy.

In the core series
One-hit KO moves deal damage so that the target faints. If the target faints, the game displays the message "It's a one-hit KO!" (or simply "One-hit KO!" in Generation I).

In Generations and, super effective one-hit knockout moves display the super effective message and play the appropriate sound effect. From Generation III onward, type-effectiveness messages no longer appear, but appropriate type-effectiveness sound effects still play.

Pokémon with the Ability are immune to one-hit KO moves. Pokémon with are also immune, unless the one-hit KO move's type is super effective against that Pokémon. A Focus Sash or can allow a Pokémon to survive a one-hit KO move.

All OHKO moves have a base of 5. If an OHKO move becomes a Z-Move, it will have a power of 180.

Generation I
All OHKO moves have an accuracy of 30%, but they will automatically fail if the user's stat is lower than the target's. An X Accuracy will guarantee that all OHKO moves hit. The accuracy of OHKO moves in Generation I is affected by the standard and  stats.

Generation II
OHKO moves automatically fail if the target has a higher level than the user. Their accuracy starts at 76/256 (approximately 30%) and increases by 2/256 (approximately 0.8%) for each level the user is above the target. This means that if the user's level is 90 levels greater than the target's, the move will have 100% accuracy. An X Accuracy will guarantee that all OHKO moves hit. The accuracy of OHKO moves in Generation II is affected by the standard accuracy and evasion stats.

Generation III onward
OHKO moves automatically fail if the target has a higher level than the user. Their accuracy starts at 30% and increases by 1% for each level the user is above the target. and stats no longer influence the move's accuracy, including modifiers from items such as Wide Lens or  such as. Effects that allow moves to always hit (such as or ) still work on OHKO moves.

In Generation VII, the accuracy of starts at 20% instead if the user is not. In addition, all OHKO moves now display their accuracy as 30% instead of —, although the calculation remains unchanged (except for Sheer Cold used by a non-Ice-type Pokémon).

In the Pokémon Mystery Dungeon series
In the Pokémon Mystery Dungeon series of games, OHKO moves can hit regardless of level, although they are very prone to missing as always. When one hits, the game states that the target fainted through "calamitous damage" (changed to the standard "It's a one-hit KO!" in ). However, they actually do 9999 damage, which can be seen when the attacks are reflected by such as Counter Hitter if the Pokémon is revived by a.

Trivia

 * can learn the most one-hit KO moves of any Pokémon (excluding Smeargle), being able to learn, , and.
 * Starting in Generation VII, all one-hit KO moves are normally ineffective against one type. cannot affect  Pokémon,  and  cannot affect  Pokémon, and (starting in Generation VII)  cannot affect  Pokémon.
 * Immunity to Sheer Cold is the only one not based on a type immunity, and thus cannot be bypassed (e.g. with, , or a Ring Target). Sheer Cold is also the only one-hit KO move where this immunity did not exist until after its debut generation.
 * Starting in Generation VII, Sheer Cold is the only one-hit KO move with different accuracy mechanics from other one-hit KO moves.
 * Sheer Cold is the only one-hit knockout move to be introduced after Generation I.