Once per turn

Once per turn
Japanese	１ターンに１度（ど）
Japanese (ruby)	１ターンに１ど
Japanese (base text)	１ターンに１度
Japanese (romanized)	1 Tān ni 1 Do
English	once per turn
Other names French: une fois par tour German: einmal pro Spielzug Italian: una volta per turno Korean: 1턴에 1번 (1 Turn ? 1 番) 1 Teon-e 1 Beon Portuguese: uma vez por turno Spanish: una vez por turno Traditional Chinese: 每回合1次 Měi Huíhé 1 Cì / Mui5 Wui4 hap6 1 Ci3 Formerly: 每1回合1次 Měi 1 Huíhé 1 Cì / Mui5 1 Wui4 hap6 1 Ci3

"Once per turn effects" are a kind of card effect. There are three kinds of "Once per turn effects".

The first is typically referred to as a "Once per turn effect". The second is typically referred to as a "Only once per turn effect". The third is typically referred to as an "Additional Normal Summon once per turn effect".

Once per turn effects

These kinds of effects can be seen by the fact that the effect starts with "once per turn" and possibly another Activation Requirement as well.

Example:

• Once per turn: You can detach 1 Xyz Material from this card, then target 1 Defense Position monster on the field; change it to face-up Attack Position, and if you do, it loses 600 ATK.

Typically, these kinds of effects are either Ignition Effects or Quick Effects, but they can also be Trigger Effects. These kinds of effects can only be used once per turn as long as that specific card stays face-up on the field. For example, if "Photon Papilloperative" activates its effect, and then is later destroyed that turn, and "Xyz Reborn" is used to Special Summon it back from the Graveyard, then you can once again use the effect as it has left the field, which "resets" the once per turn condition, thereby allowing it to activate once again. This principle also applies for Spell and Trap Cards. If you control multiple of the same card, you can activate both of their effects as well.

Only once per turn effects

These kinds of effects can be seen by the fact effect has either "You can only activate 1 "X" per turn" or "You can only activate/use the/this effect of "X" once per turn." Cards stating "once per Duel" instead work in the same way (they just apply for the entire Duel instead).

Like with "once per turn effects", these can be Ignition Effects, Quick Effects or Trigger Effects; however, unlike them, these effects can only be used once per turn, regardless of them being reset, or you having multiple copies.

Japanese: このカード名の (Effect #) 効果は１ターン（デュエル）に１度しか使用（発動）できない。(Kono kādo na no (Effect #) kōka waāō)

Example 1 (Spellbook of Secrets): Add 1 "Spellbook" card from your Deck to your hand, except "Spellbook of Secrets". You can only activate 1 "Spellbook of Secrets" per turn.

This means you cannot activate multiple copies of "Spellbook of Secrets", since it states you can only activate one of them per turn. However, if the activation of a cards with such statements is negated, you can activate it once again.

Example 2 (Bacon Saver): During either player's Battle Step, while an attack is occurring: You can banish this card from your Graveyard; negate the attack. You can only use the effect of "Bacon Saver" once per Duel.

If a card states "You can only use this effect of (card name) once per turn", then even if the activation is negated, you cannot activate it once again.

This kind of condition is not affected by cards' names being changed on the field. For example, if "Fairy Archer" activates its effect, even its name is changed by "Hero Mask" later that turn, it cannot activate its effect again that turn.

You can only gain this effect once per turn

Unlike the other "Once per turn" effects, these work a bit differently. These can be identified by the text "(You can only gain this effect once per turn.)". Most such effects allow the player to perform an additional Normal Summon/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 the turn this card was Normal Summoned, you can Normal Summon 1 "lswarm" monster in addition to your Normal Summon/Set. (You can only gain this effect once per turn.)"

Cards and effects that start a Chain, then perform the Normal Summon immediately after resolving (such as "Pahunder" and "Ultimate Offering") as well as cards and effects that change the maximum number of Normal Summon/Sets that turn (such as "Double Summon" and "Chain Summoning") can still be used, regardless of if an effect that specifies "(You can only gain this effect once per turn.)" was used that turn.