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| kanji = １ターンに１{{ruby|度|ど}} | japanese = １ターンに１度 | furigana = １ターンに１ど | romaji = 1 Ichi Tān ni 1 Do | japanese translated = | english = Once once per turn | french = Une une fois par tour | german = Einmal einmal pro Spielzug | italian = Una una volta per turno | korean = 1턴에 1번 (1 Turn ? 1 番) ''1 Teon-e 1 Beon''|chinese =每回合1次 ''Měi Huíhé 1 Cì/ Mui5 Wui4 hap6 1 Ci3'' (formerly <br/>Formerly: 每1回合1次 ''Měi 1 Huíhé 1 Cì/ Mui5 1 Wui4 hap6 1 Ci3'') | portuguese = Uma uma vez por turno | spanish = Una una vez por turno

Some cards and [[card effect|effects]] can only be activated '''"Once once per turn effects"''' . There are a kind of [[three distinct ways in which this limitation is commonly applied. =="Once per turn"=={{Show card effect]] found on image|Barrel Dragon|size=200px}}"Once per turn" effects can be identified by the text "once per turn" in their [[Effect Monsteractivation requirement|activation conditions]]. These kinds of effects can only be used once per turn per card, while that card is face-up in its current location. (Even if that effect's, activation is [[Spell Cardnegate]]s and d, it cannot be activated again that turn.) This restriction only applies to that copy of the card; if a player is in [[Trap Cardpossession]]s. There are three kind of multiple cards with the same name that have the same "Once per turn effects"effect, they can activate each one during that turn. The first is typically referred to as Additionally, if a card that activated its "Once per turn effects"effect leaves its current location (the entire field is considered the same location) or is flipped face-down, its effect can be activated again during that same turn. The second is typically referred to as  For example, if "[[Barrel Dragon]]"Only once per [[activate]]s its effect, it cannot activate its effect again that turn effects"while it remains face-up on the field. The third However, if after activating its effect it is typically referred [[destroy]]ed and sent to as the [[Graveyard]], then [[Special Summon]]ed from the Graveyard by "Additional [[Normal SummonCall of the Haunted]] once per ", it can then activate its effect again during that turn . Similarly, if a player controls two copies of "Barrel Dragon", they can activate the effects"of both during the same turn.

==Once per turn effects==These kinds A small number of effects can be seen by the fact cards have non-activated [[Continuous Effect]]s that the effect starts with "also have a once per turnclause (e.g. " and possibly another [[Activation RequirementZW - Pegasus Twin Saber]] as well"). In their cases, they can only each apply their effects once per turn, without activating.

Example:* '''Once per turn:''' You can An exception to the above rules are monsters that specifically change themselves to [[detachface-down]] 1 [[Xyz MaterialDefense Position]] from this card, then (such as "[[targetSwarm of Locusts]] 1 " and "[[Defense PositionFlip Flop Frog]] monster on "): the same card cannot activate such an effect again for that turn after the [[field]]; change next time it to [[is flipped face-up]] [[Attack Position]]. However, multiple copies can still use the effect once each, also if one such card leaves the field and then returns, or if you doit is flipped face-down by another card's effect then flipped face-up once again, it loses 600 [[ATK]]the effect will still reset.{{-}}

Typically, these kinds =="Only once per turn"=={{Main|Only once per turn}}{{Show card image|Spellbook of Secrets|size=200px}}"Only once per turn" effects are either [[Ignition Effects]] or [[Quick Effects]], but they can also be identified by one of the following [[Trigger Effectscondition]]. These kinds of effects s: "You can only be used once activate 1 "X" per turn as long as that specific card stays face-up on the field. For example, if [[Photon Papilloperative]] [[" or "You can only activate]]s its effect, and then is later [[destroy]]ed that turn, and [/use [Xyz Reborn]] is used reference to [[Special Summoneffect]] it back from the [[Graveyard]], then you can once again use the effect as it has left the field, which of "resetsX" the once per turn condition, thereby allowing it to activate once again" (Japanese: このカード名の (''Effect #'') 効果は１ターンに１度しか使用（発動）できない。). This principle also applies for Spell and Trap Cards. If you control multiple stating "once per Duel" instead of "once per turn" (Japanese: ・・・(''Effect #'') 効果は１デュエルに１度・・・) work in the same cardway, you can activate both of their effects as wellbut apply for the entire Duel instead.

[[File:PhotonPapilloperative-SP14-EN-SFR-1EThe reference to the effect is most often "the effect" or "this effect", but can also be other references such as "1 of these effects", "each of the preceding effects" etc. depending on the structure of the card's text.png|center]]

==Only once per turn effects==These kinds of effects can be seen by the fact If an effect has either "You this condition, each player can only activate 1 "card name" per turn" or "You can only activate/use this that effect of "card cards with the same name" once per turn.This kind of condition is not affected by cards' names being changed; for example, if "[[Fairy Archer]]" These kinds of effects also apply to any card saying activates its effect, even its name is changed by "once per Duel[[Hero Mask]]" and acts the exact same as later that turn, it would had it said "once per cannot activate its effect again that turn" instead.<ref>{{cite book |author=Konami |title=Yu-Gi-Oh! Official Card Game - Perfect Rulebook 2015 |url=https://ygorganization.com/perfectrulebook/ |page=47}}</ref>

Example 1:* [[Add]] 1 "[[Spellbook]]" If a card from your [[Deck]] to your [[hand]], except states "[[Spellbook You can only '''use''' this effect of Secrets]]". (''card name'') once per turn", then even if the activation is negated, you cannot activate it once again. On the other hand, if a card states "You can only '''activate 1 "Spellbook ''' this effect of Secrets(''card name'') once per turn" per , that effect can be activated again that turnif its activation is negated.'''

:Example 2:* During either player's 1 ("[[Battle StepSpellbook of Secrets]], while an "): [[attackAdd]] is occurring: You can 1 "[[banishSpellbook]] this " card from your Graveyard; [[negateDeck]] to your [[hand]], except "[[Spellbook of Secrets]] the attack". '''You can only use the effect activate 1 "Spellbook of Secrets"[[Bacon Saver]]" once per [[Duel]]turn.'''If a player activates "Spellbook of Secrets" and its activation is not negated, this means that player cannot activate the card "Spellbook of Secrets" again during that turn. If a player activates it and its activation was negated, the player may activate another one during the same turn if they have another one.

Like with :Example 2 ("once per turn effects[[Bacon Saver]]"): During either player's [[Battle Step]], these while an [[attack]] is occurring: You can be Ignition Effects, Quick Effects or Trigger Effects, though unlike them, these can only be used once per turn, regardless of them being reset, or you having multiple copies[[banish]] this card from your Graveyard; [[negate]] the attack. This means you cannot activate multiple Spellbook of Secrets, since it states you '''You can only activate one use the effect of them "[[Bacon Saver]]" once per turn[[Duel]]. If the activation of a card that states "You can only '''activate''' this If a player activates the effect of "card nameBacon Saver" once per turn" is negated, then this means you can that player cannot activate it once again. However, if a card states "You can only '''use''' this the effect of "card name" once per turnBacon Saver"again during that same Duel, then even if the negation is activation of the effect was negated, you cannot activate it once again.

Some cards apply a single limitation to multiple effects. In that case, if a player activated any of those effects, they cannot activate any of the other effects during the same turn.:Example 3 ("[[FileFluffal Bear]]"):SpellbookofSecrets-REDU-EN-UR-UEYou can [[send]] this card from your [[hand]] to the [[Graveyard]]; [[Set]] 1 "[[Toy Vendor]]" directly from your [[Main Deck|Deck]] to your [[Spell & Trap Zone]].pngYou can [[Tribute]] this card, then [[target]] 1 "[[Polymerization]]" in your Graveyard; [[Add a card|centeradd]] it to your hand. '''You can only use 1 "Fluffal Bear" [[effect]] per [[turn]], and only once that turn.'''If a player activates either effect of "Fluffal Bear", they cannot activate that effect again, or the other effect, during that same turn.{{-}}

=="You can only gain this effect once per turn"==Unlike the other "Once {{Main|Gain this effect once per turn" }}{{Show card image|Constellar Pollux|size=200px}}These effects, these work a bit differently. These can be identified by the text "(You can only gain this effect once per turn.)". All such effects allow the player to perform an additional [[Normal Summon]]/[[Normal Set|Set]] that turn without starting a [[Chain]], but only one of these effects can be gained per turn. Even if the player controls both "[[Evilswarm Castor]]" and "[[Fire Formation - Tensu]]", the player still can only gain the effect of one to perform an extra Normal Summon.

Example:* "During Each player can only apply one effect with this text per turn, even if the turn this card was Normal Summonedcards have different names or different effects. For example, you can Normal Summon 1 even if the player controls both "[[lswarmEvilswarm Castor]]" monster in addition to your Normal Summon/and "[[Normal Set|SetFire Formation - Tensu]]. '''(You ", the player can only gain this the effect once per turnof one to perform an extra Normal Summon.)'''<ref>{{cite web |title=「鬼ガエル」のモンスター効果と、「海皇の重装兵」のモンスター効果のどちらを適用して、モンスターを召喚するかを選べますか？ |trans-title=Can I choose whether to apply the monster effect of "Swap Frog" or the monster effect of "Atlantean Heavy Infantry" when I Summon a monster? |url=https://www.db.yugioh-card.com/yugiohdb/faq_search.action?ope=5&fid=12842&request_locale=ja |website=Yu-Gi-Oh! Official Card Game Card Database |publisher=Konami |access-date=22 June 2022 |date=24 March 2017}}</ref>

Cards and Most effects that start a with this text allow the player to perform an additional [[ChainNormal Summon]], then perform the Normal Summon immediately after /[[ResolveNormal Set|resolvingSet]] (such as "that turn without starting a [[PahunderChain]]" and . The only cards with this text that do not have such an effect are "[[Ultimate OfferingZefraath]]") as well as cards and effects that change the maximum number of Normal Summon/Sets that turn (such as "which grants an additional [[Double Pendulum Summon]]" ) and "[[Chain SummoningDice Re-Roll]]") can still be used, regardless of if an effect that specifies "(You can only gain this effect once per turn.which allows a player to redo a dice roll)" was used that turn.{{-}}