A Trigger Effect is a type of monster effect that is activated at a specific time. This can either be in response to a specific event or during a particular phase or step. Unless otherwise specified, Trigger Effects can be activated during either player’s turn.
Trigger Effects are Spell Speed 1 and therefore cannot be chained to other effects, except when multiple Trigger Effects want to be activated simultaneously, in which case they will form a Chain with each other according to the rules for simultaneous effects.
Trigger Effects that are activated in response to a specific event, such as a card being destroyed, or a card being added to the hand, are activated in the yellow box of the "Fast effect timing" chart, and must either be activated at this point, or not at all. Examples include "Jurrac Guaiba" and "Number 39: Utopia".
For optional Trigger Effects that activate "when" a specific action occurs, their trigger must have been the last thing to happen, or else the effect cannot be activated. See If... You Can VS When... You Can for more information.
Trigger Effects that are not triggered by a specific event, but rather by a particular period of time, such as the Standby Phase, can be activated when the player has the right to perform an action and only during an open game state. This means that they can only ever be activated as Chain Link 1. In this regard, their function is more similar to Ignition Effects (except that they are activated outside the Main Phase) as the player can choose at which point during that time to activate the effect. Examples include "Fire King High Avatar Garunix" and "Scarm, Malebranche of the Burning Abyss".
The Damage Step
Trigger Effects that are activated at a particular part of the Damage Step, such as the effect of "Ally of Justice Catastor", activate immediately upon their effect being triggered, similar to other Trigger Effects that are activated in response to a specific event. Multiple Trigger Effects of this nature will form a Chain in accordance with the rules for simultaneous effects.
For whether or not a Trigger Effect whose trigger does not exclusively occur during the Damage Step can be activated during the Damage Step, it is best to consider each card on a case-by-case basis. Usually, if such a Trigger Effect cannot be used at that time, its TCG text will state "except during the Damage Step," though this is not always the case.
Spell/Trap effects that trigger
Spell and Trap Cards can also have effects that trigger. When the effect of an already-face-up Spell or Trap Card is triggered, the effect functions just like the Trigger Effect of a monster and activates in the yellow box of the "Fast effect timing" chart. If multiple effects are triggered, monster or otherwise, the rules for simultaneous effects are followed.
Continuous Trap Cards
If a Continuous Trap Card has an effect that triggers, it is also possible to activate both the Trap Card and its effect in the same Chain Link in response to the event that triggers the effect at the time when the player has the right to activate a fast effect.
For example, if a monster you control is destroyed by battle whilst you control a face-up "Yang Zing Creation", if you choose to activate the effect of this face-up "Yang Zing Creation", you must do so in the yellow box of the "Fast effect timing" chart, before either player can activate fast effects. If, however, "Yang Zing Creation" is face-down on the field when the monster is destroyed by battle, so long as the monster being destroyed is still the last thing to happen, you can activate the effect of "Yang Zing Creation" in the same Chain Link as the card itself.
Continuous Trap Cards which have effects that state they must be activated while the Trap Card is already face-up on the field, such as "Predaplanet", cannot activate that effect in the same Chain Link as the Trap Card itself.
Further, Continuous Trap Cards which have rulings that state that their effect cannot be activated in the same Chain Link as the card itself must have first been activated, and resolved, for an action to be able to trigger their effects. These include "All-Out Attacks", "Coffin Seller", "Cyber Summon Blaster", "Light Spiral", "Natural Disaster", "Overdoom Line", "PSY-Frame Accelerator", "Spirit's Invitation", "Swiftstrike Armor", and "Unpossessed".
List of TCG and OCG monsters with Trigger Effects
|Japanese name||Rank||Level||Attribute||Type||Card type||ATK||DEF|
|D.D. Crazy Beast||3||EARTH||Beast||Monster Card||1,400||1,400|
|Toon Gemini Elf||トゥーン・ヂェミナイ・エルフ||4||EARTH||Spellcaster||Monster Card||1,900||900|
|Nightmare Wheel||Trap Card|
|Phantom Beast Rock-Lizard||7||DARK||Beast-Warrior||Monster Card||2,200||2,000|
|Charming Resort Staff||「||3||LIGHT||Fairy||Monster Card||300||200|
|Masked Chopper||マスクド・チョッパー||1||EARTH||Fiend||Monster Card||100||100|
|Skull Conductor||スカル・コンダクター||4||DARK||Zombie||Monster Card||2,000||0|
|Mirage Knight||8||LIGHT||Warrior||Monster Card||2,800||2,000|
|Dododo Swordsman||ドドドガッサー||8||EARTH||Warrior||Monster Card||0||3,000|
|... further results|
List of OCG/TCG Spell/Trap Cards with effects that trigger
- Note: This list is incomplete
|Japanese name||Primary type||Secondary type||Attribute||Type||Level/|
|Adhesive Explosive||Effect Monster||WIND||Machine||0003||00001000||00001000|
|Alien Warrior||エーリアン・ウォリアー||Effect Monster||EARTH||Reptile||0004||00001800||00001000|
|Ally of Justice Catastor||Synchro Monster|
|Ally of Justice Field Marshal||Synchro Monster|
|Ally of Justice Reverse Break||Effect Monster||DARK||Machine||0004||00001200||00001200|
|Amazoness Blowpiper||アマゾネスの||Effect Monster||EARTH||Warrior||0003||00000800||00001500|
|Ambulance Rescueroid||レスキューキューロイド||Effect Monster|
|... further results (3354 more)|
|Japanese name||Card type||Property|
|Abyss Script - Opening Ceremony||Spell Card||Normal Spell Card|
|Aquarium Stage||Spell Card||Continuous Spell Card|
|Armed Changer||アームド・チェンジャー||Spell Card||Equip Spell Card|
|Attack the Moon!||ムーン・スクレイパー||Spell Card||Continuous Spell Card|
|Blackwing - Boobytrap||Trap Card||Normal Trap Card|
|Boss Rush||ボスラッシュ||Spell Card||Continuous Spell Card|
|Burning Land||Spell Card||Continuous Spell Card|
|Butterfly Dagger - Elma||Spell Card||Equip Spell Card|
|Card of Safe Return||Spell Card||Continuous Spell Card|
|Celestial Sword - Eatos||Spell Card||Equip Spell Card|
|... further results (590 more)|