Accuracy: Difference between revisions

4,978 bytes removed ,  7 August 2016
rewording; replaced "base accuracy" by "accuracy" (the page title); removed everything that does not belong to move accuracy (and already is on our stat page, even in more detail); in other languages
(→‎1/256 miss glitch: Changed some wording around because I don't believe moves ARE labeled in such a way anyway in Generation I if I remember right. Less the game misinforms the player and more the game doesn't work as we know now it was intended.)
(rewording; replaced "base accuracy" by "accuracy" (the page title); removed everything that does not belong to move accuracy (and already is on our stat page, even in more detail); in other languages)
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{{samename|in-battle stat|Statistic#Accuracy|Statistic → Accuracy}}
{{samename|in-battle stat|Statistic#Accuracy|Statistic → Accuracy}}
'''Accuracy''' (Japanese: '''めいちゅう''' ''accuracy'') is an aspect of moves that determine how often they can hit their target.
'''Accuracy''' (Japanese: '''めいちゅう''' ''accuracy'') is an aspect of [[move]]s that, in conjunction with the user's in-battle {{stat|accuracy}} stat and the target's {{stat|evasion}} stat, determines how reliable they can hit their target. Although the concept was introduced in [[Generation I]], a move's accuracy was not displayed until [[Generation III]].  


A move's base accuracy currently can be any number from 1-100, reflecting the probability of the move hitting as a percentage; moves' accuracy was not visible to the player until the Generation III games. While values from 1-100 for accuracy are possible, only values from 30-100 are used, and they are only used in multiples of 5.
A move's accuracy can be any number from 1-100, reflecting the probability of the move being successful as a percentage (if neither {{stat|accuracy}} nor {{stat|evasion}} are modified in-battle). Currently, however, only multiples of 5 between 30 and 100 (inclusive) are used.


Many moves have an accuracy of "—%", indicating that they are exempt from accuracy calculations. This is usually because they affect no one but the user (and/or the partner in a [[Double Battle]]), or because they will never miss the target unless the target uses a move that grants semi-invulnerability for a turn (such as {{m|Fly}} or {{m|Dig}}).
Many moves have an accuracy of "—%", indicating that they are exempt from accuracy calculations and will be successful regardless. Oftentimes, these moves affect no one but the user (and/or the partner in a [[Double Battle]]), or are simply intended to be {{cat|moves that cannot miss}} (unless the target has used {{cat|Moves with a semi-invulnerable turn|a move that grants it semi-invulnerability for a turn}} such as {{m|Fly}}).
 
Accuracy can be increased by [[Ability|Abilities]], [[held item]]s, and increasing the accuracy stat; {{a|Compound Eyes}} raises the Pokémon's accuracy by 30%, {{a|Victory Star}} raises a Pokémon's accuracy by 10%, the {{DL|In-battle effect item|Wide Lens}} raises the holder's accuracy by 10%, and the {{DL|In-battle effect item|Zoom Lens}} raises the holder's accuracy by 20% if the holder moves after its target. The accuracy stat can be increased by {{m|Acupressure}}, {{m|Hone Claws}}, {{m|Coil}}, {{a|Moody}}, and {{DL|Battle item|X Accuracy}}{{tt|*|Generation III onwards; in the first two generations X Accuracy simply makes Pokémon's moves ignore the accuracy check}}.
 
Accuracy can be decreased by {{Abilities}}, [[held item]]s, and [[move]]s. {{a|Hustle}} decreases the accuracy of the Pokémon's [[physical move]]s by 20%. The accuracy stat can be decreased by {{m|Flash}}, {{m|Kinesis}}, {{m|Mirror Shot}}, {{m|Mud Bomb}}, {{m|Mud-Slap}}, {{m|Muddy Water}}, {{m|Octazooka}}, {{m|Sand Attack}}, {{m|Smokescreen}}, and {{m|Secret Power}} when used in the sand, on plain terrain{{sup/4|DPPtHGSS}}, in [[puddle]]s{{sup/4|DPPtHGSS}}, and on rocks{{sup/6|XYORAS}}.
 
==Formula for accuracy and evasion==
The probability that a move will hit is calculated as follows:
 
[[File:Accuracy calc.png]]
 
Where:
*''A<sub>base</sub>'' is the base accuracy of the move (in percent - e.g. a base accuracy of 95 is counted as 0.95),
*''Accuracy'' is the current accuracy stat of the user (in percent - e.g. raising accuracy by three stages raises this number to 2), and
*''Evasion'' is the current evasion stat of the target (in percent - e.g. lowering evasion by two stages lowers this number to 0.6).
 
If P is greater than 1, the move will surely hit. In a Double or Triple Battle, it is possible for a move that targets multiple Pokémon to hit some and miss others—the probabilities are calculated individually for each Pokémon.
 
===Application of stat modifiers===
{| class="roundy" style="margin:auto; margin-bottom:15px; text-align:center; background:#FAFAD2; border:3px solid #000" cellspacing="1" cellpadding="3"
|+ '''Stage multipliers'''
|-
! Stage (accuracy)
| -6 || -5 || -4 || -3 || -2 || -1 || 0 || +1 || +2 || +3 || +4 || +5 || +6
|-
! Stage (evasion)
| +6 || +5 || +4 || +3 || +2 || +1 || 0 || -1 || -2 || -3 || -4 || -5 || -6
|-
! Gen I
| <sup>25</sup>/<sub>100</sub> || <sup>28</sup>/<sub>100</sub> || <sup>33</sup>/<sub>100</sub> || <sup>40</sup>/<sub>100</sub> || <sup>50</sup>/<sub>100</sub> || <sup>66</sup>/<sub>100</sub> || <sup>100</sup>/<sub>100</sub> || <sup>150</sup>/<sub>100</sub> || <sup>200</sup>/<sub>100</sub> || <sup>250</sup>/<sub>100</sub> || <sup>300</sup>/<sub>100</sub> || <sup>350</sup>/<sub>100</sub> || <sup>400</sup>/<sub>100</sub>
|-
! Gen II
| <sup>33</sup>/<sub>100</sub> || <sup>36</sup>/<sub>100</sub> || <sup>43</sup>/<sub>100</sub> || <sup>50</sup>/<sub>100</sub> || <sup>60</sup>/<sub>100</sub> || <sup>75</sup>/<sub>100</sub> || <sup>100</sup>/<sub>100</sub> || <sup>133</sup>/<sub>100</sub> || <sup>166</sup>/<sub>100</sub> || <sup>200</sup>/<sub>100</sub> || <sup>233</sup>/<sub>100</sub> || <sup>266</sup>/<sub>100</sub> || <sup>300</sup>/<sub>100</sub>
|-
! Gen III-IV
| <sup>33</sup>/<sub>100</sub> || <sup>36</sup>/<sub>100</sub> || <sup>43</sup>/<sub>100</sub> || <sup>50</sup>/<sub>100</sub> || <sup>60</sup>/<sub>100</sub> || <sup>75</sup>/<sub>100</sub> || <sup>100</sup>/<sub>100</sub> || <sup>133</sup>/<sub>100</sub> || <sup>166</sup>/<sub>100</sub> || <sup>200</sup>/<sub>100</sub> || <sup>250</sup>/<sub>100</sub> || <sup>266</sup>/<sub>100</sub> || <sup>300</sup>/<sub>100</sub>
|-
! Gen V+
| <sup>3</sup>/<sub>9</sub> || <sup>3</sup>/<sub>8</sub> || <sup>3</sup>/<sub>7</sub> || <sup>3</sup>/<sub>6</sub> || <sup>3</sup>/<sub>5</sub> || <sup>3</sup>/<sub>4</sub> || <sup>3</sup>/<sub>3</sub> || <sup>4</sup>/<sub>3</sub> || <sup>5</sup>/<sub>3</sub> || <sup>6</sup>/<sub>3</sub> || <sup>7</sup>/<sub>3</sub> || <sup>8</sup>/<sub>3</sub> || <sup>9</sup>/<sub>3</sub>
|}
In Generations I and II, accuracy and evasion stages are resolved separately and both multipliers applied to the move's accuracy to determine the final chance of a move hitting or missing. For example, a Pokémon with -1 accuracy using a move that has 100% accuracy on a target with +1 evasion would have a <sup>66</sup>/<sub>100</sub> * <sup>66</sup>/<sub>100</sub> ~= 43.56% chance of hitting in Generation I, or a <sup>75</sup>/<sub>100</sub> * <sup>75</sup>/<sub>100</sub> ~= 56.25% chance of hitting in Generation II. In Generation III, this was changed so that the stages of the two stats are now combined before determining the multiplier, with the evasion stage subtracted from the accuracy stage. Therefore, in the above situation, the attacking Pokémon would have a <sup>60</sup>/<sub>100</sub> = 60% chance of hitting.<ref>[http://www.dragonflycave.com/statstages.aspx Dragonfly Cave on stat stages mechanics]</ref>
 
Additionally, the combined stages are capped at -6 and +6 from Generation III onward, meaning that a Pokémon with minimum accuracy attacking a target with maximum evasion will have no lower than a <sup>33</sup>/<sub>100</sub> or 33% chance to hit. (For comparison, in Generation II, the attacker would only have a <sup>33</sup>/<sub>100</sub> * <sup>33</sup>/<sub>100</sub> ~= 10.89% chance of hitting.)


==1/256 miss glitch==
==1/256 miss glitch==
In the [[Generation I]] handheld games, even moves with 100% accuracy had a chance to miss for seemingly no reason whatsoever. This was due to accuracy being internally stored as a single byte ranging from 0 to 255 (0 to FF in hexadecimal), and the probability of a move hitting being determined by comparing a randomly generated byte to the accuracy value, with the move hitting if it was less and missing if it was equal or greater. There was therefore a 1/256 chance of the random byte being equal to 255, which could never be less than even the highest possible accuracy value, causing moves intended to be 100% accurate to miss 1/256 of the time and yielding an effective accuracy of about 99.6%. This bug also applied to secondary effects such as poison or paralysis,{{fact}} as well as [[critical hit]]s. (It was not possible to replace the "less than" check with a "less than or equal to" check, as this would enable any of these events with an accuracy value of 0 to succeed 1/256 of the time when the random byte was equal to 0.) {{m|Swift}} was unaffected, as its effect automatically skips all accuracy checks (including the invulnerability effects of {{m|Fly}} and {{m|Dig}}) and thus truly has 100% accuracy.
In the [[Generation I]] handheld games, moves with 100% accuracy had a chance to miss if neither accuracy nor evasion stats were modified. This was due to accuracy being internally stored as a single byte ranging from 0 to 255 (0 to FF in hexadecimal), and the probability of a move hitting being determined by comparing a randomly generated byte to the accuracy value, with the move hitting if it was less and missing if it was equal or greater. There was therefore a 1/256 chance of the randomly generated byte being equal to 255, which could never be less than even the highest possible accuracy value, causing moves intended to be 100% accurate to miss 1/256 of the time and yielding an effective accuracy of about 99.6%. This bug also applied to secondary effects such as {{status|poison}} or {{status|paralysis}},{{fact}} as well as [[critical hit]]s. (It was not possible to replace the "less than" check with a "less than or equal to" check, as this would enable any of these events with an accuracy value of 0 to succeed 1/256 of the time when the random byte was equal to 0.) {{m|Swift}} was unaffected, as its effect automatically skips all accuracy checks (including the invulnerability effects of {{m|Fly}} and {{m|Dig}}) and thus truly has 100% accuracy.


The bug was partially fixed in {{g|Stadium}} by allowing the move to hit if the random byte was either less than the accuracy value or exactly equal to 255; this fix effectively causes every move in the game to hit 1/256 more often. The fix did not apply to critical hits, which were still capped at a 255/256 probability. It was further fixed in [[Generation II]], which removed this extra check and instead allowed moves calculated to have 100% accuracy (after applying all modifiers) to skip the random byte generation entirely. However, this did not apply to {{m|Protect}}, which still has a 1/256 chance to fail when used for the first time. <!-- TODO: What about Stadium 2? --> All 1/256-related bugs were finally resolved in [[Generation III]], whose hardware gained the ability to more freely generate ranges of random numbers; move accuracies are stored as a number from 0 to 100, and the game performs a "less than or equal to" check on a random integer from 1 to 100.
The bug was partially fixed in {{g|Stadium}} by allowing the move to hit if the random byte was either less than the accuracy value or exactly equal to 255; this fix effectively causes every move in the game to hit 1/256 more often than indicated. The fix did not apply to critical hits, which were still capped at a 255/256 probability. It was further fixed in [[Generation II]], which removed this extra check and instead allowed moves calculated to have 100% accuracy (after applying all modifiers) to skip the random byte generation entirely. However, this did not apply to {{m|Protect}}, which still has a 1/256 chance to fail when used for the first time. All 1/256-related bugs were finally resolved in [[Generation III]], where move accuracies are stored as a number from 0 to 100, and the game performs a "less than or equal to" check on a random integer from 1 to 100.


==In the Pokémon Mystery Dungeon series==
==In the Pokémon Mystery Dungeon series==
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In the Mystery Dungeon series, there are several ways of increasing the accuracy of moves. Much like in the core series games, Abilities such as {{a|Compound Eyes}} boost the accuracy of moves. Additionally, beginning from Gates to Infinity, moves can be {{DL|Pokémon Mystery Dungeon: Gates to Infinity|New mechanics|ranked up}} when they are used over time, which will also increase the move's accuracy. The increase is permanent and will carry over to other teammate's with the same move. Items such as {{DL|Gates to Infinity exclusive items|Items that affect moves|Accuracy Manual}}s{{sup/md|GTI}} or {{DL|Health drink|List of health drinks|Accuracy Drink}}s{{sup/md|SMD}} can also permanently increase accuracy. Certain [[emera]]s can also increase accuracy when added to [[looplet]]s.
In the Mystery Dungeon series, there are several ways of increasing the accuracy of moves. Much like in the core series games, Abilities such as {{a|Compound Eyes}} boost the accuracy of moves. Additionally, beginning from Gates to Infinity, moves can be {{DL|Pokémon Mystery Dungeon: Gates to Infinity|New mechanics|ranked up}} when they are used over time, which will also increase the move's accuracy. The increase is permanent and will carry over to other teammate's with the same move. Items such as {{DL|Gates to Infinity exclusive items|Items that affect moves|Accuracy Manual}}s{{sup/md|GTI}} or {{DL|Health drink|List of health drinks|Accuracy Drink}}s{{sup/md|SMD}} can also permanently increase accuracy. Certain [[emera]]s can also increase accuracy when added to [[looplet]]s.
==In other languages==
{{langtable|color={{physical color}}|bordercolor={{physical color light}}
|zh_yue=命中率
|fr=Précision
|de=Genauigkeit
|it=Precisione
|ko=
|pl=Accuracy
|es=
}}


==References==
==References==