Rules/Game Mechanics

If you play current format Yu-Gi-Oh!, learning the rules of Goat Format will not be difficult. Believe it or not, the vast majority of Yu-Gi-Oh!'s rules have not changed at all over the years. The differences that do exist are in many cases quite subtle. They are listed below. It's important to note here that if a rule is not explicitly listed here is being different in goat format, you can assume that it works the exact same way as it does in the current format. For specific card rulings, see our Individual Rulings page.
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Goat Format Rule #1: Start With 6

​Unlike in current Yu-Gi-Oh!, the player who goes first will draw a card at the start of their first draw phase. This means that they will initially have 6 cards in their starting hand.
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Goat Format Rule #2: Unlimited Fusion Deck and Main Deck

​Before Synchro Monsters were introduced to the game, the Extra Deck was called the Fusion Deck, and it could contain as many cards as you wanted! For "manual" online dueling simulators that restrict you to only 15 cards, use the following convention: Add the 15 Fusions that you think you will be most likely to use, and then if you happen to need one that you didn't add, simply use a different Fusion as a proxy.

• Example: You activate Snatch Steal on your opponent's Fusilier Dragon, the Dual-Mode Beast, and use Metamorphosis on it, with the intention of Summoning a King Dragun. But you did not put King Dragun in your 15-card Fusion Deck. You inform your opponent of this fact, special Summon a Darkfire Dragon from your Fusion Deck instead, and say, "This Darkfire Dragon will represent a King Dragun." You then send your opponent a link to King Dragun's text so that they know what it does.
  

Additionally, in Goat Format, the Main Deck was allowed to be unlimited as well. One person even took a 2,222-card deck to a national tournament! Unfortunately, however, most online dueling simulators will not allow more than 60 cards to be placed into a deck, and there is no easy work-around. Finally, Side Decks were treated slightly differently than they are today; players were technically not allowed to use Side Decks with more than 0 but less than 15 cards. But this is rarely, if ever, enforced today.
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Goat Format Rule #3: One Field Spell to Rule Them All

It is not possible for both players to control a face-up active Field Spell card. If the activation of a Field Spell resolves while the opponent controls a face-up Field Spell, the previous Field Spell is destroyed. It's worth noting that Field Spells must remain face-up in order to resolve.

• Example 1: Player A controls a face-up Necrovalley. Player B activates A Legendary Ocean. Player A has no response, and Necrovalley is destroyed.
• Example 2: Player A controls a face-up Necrovalley. Player B sets A Legendary Ocean face-down. Player A's Necrovalley will remain face-up on the field.
• Example 3: Player A controls a face-up Necrovalley. Player B activates A Legendary Ocean. Player A Chains Mystical Space Typhoon, targeting A Legendary Ocean. Player B has no response. A Legendary Ocean was destroyed, so it does not resolve, and Necrovalley will remain face-up on the field.
  

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Goat Format Rule #4: Priority for Ignition Effects

Priority is often misunderstood by newer Goat Format players, but it's actually not very complicated. The current format rules on what Konami calls "fast effect timing" and "open and closed gamestates" can be found here. This is the same mechanic as what people in 2005 called "priority." Believe it or not, with one exception, everything that you will find on Konami's chart is the same in Goat Format.

In current format Yu-Gi-Oh!, when a Chain or Summon has finished resolving, the turn player can activate a "fast effect" (Spell Speed 2 or higher) before the opponent can. In Goat Format, when a Chain or Summon has finished resolving, the turn player can activate a "fast effect" or a monster's Ignition Effect before the opponent is allowed to respond. This change does not affect how Trigger Effects work.

• Example 1: Player A Summons Tribe-Infecting Virus. Player A can activate the effect of Tribe-Infecting Virus before Player B can activate Book of Moon.
• Example 2: Player A controls a face-up Cannon Soldier and Summons Sangan. Player A can activate the effect of Cannon Soldier, tributing Sangan, before Player B can activate Torrential Tribute.
• Example 3: Player A Summons Breaker the Magical Warrior, and its Trigger Effect to add a Spell Counter is activated. Player B may Chain Ring of Destruction to destroy Breaker the Magical and deal 1600 damage before Player A can use Breaker the Magical Warrior to destroy a Spell/Trap Card. However, if he has no response to Breaker the Magical Warrior's Trigger Effect, then the Chain will resolve, and player A can activate an Ignition Effect (such as Breaker the Magical Warrior's Ignition Effect to destroy a Spell/Trap Card) before Player B can activate his Ring of Destruction.
  

For more detail on this frequently misunderstood game mechanic, see: 6 Facts That You Should Know About Priority.
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Goat Format Rule #5: Replaying Attacks

In Yu-Gi-Oh!, a replay occurs when the number of the opponent's monsters changes during the battle step of the turn player. The attacking monster may then decide to attack the same monster, a different monster, or not attack at all. In current format Yu-Gi-Oh!, this replay mechanic is considered to be a "redirection" of the same attack, whereas in Goat Format, play rewinds back to the beginning of the Battle Step where the attack may be re-declared. This means that if the attacking player decides not to attack at all with the monster involved in the replay, it may attack again later in the battle phase.

Example 1: Player A controls an Airknight Parshath and a D.D. Warrior Lady. He declares a direct attack with Airknight Parshath, and Player B activates Call of the Haunted, Special Summoning Dark Magician. A replay occurs, and Player A attacks Dark Magician with D.D. Warrior Lady, using its effect. Then Airknight Parshath attacks directly.
Example 2: Player A attacks directly with D.D. Warrior Lady. Player B activates Call of the Haunted, Special Summoning Sangan. A replay occurs, and Player A has D.D. Warrior Lady attack Sangan. Player B activates Sakuretsu Armor to destroy D.D. Warrior Lady.
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Goat Format Rule #6: Continuous Traps with Ignition-Like Effects

​Unlike in current format Yu-Gi-Oh!, Continuous Traps with Ignition-like effects cannot be flipped face-up and use their Ignition-like effects at the same time. They must be flipped face-up "pre-emptively" so to speak. This is best demonstrated by example.

• Example 1: Player A activates Scapegoat while player B controls a facedown Royal Oppression. If player B activates his set Royal Oppression as a Chain to Scapegoat, he would not be able to also negate the activation of Scapegoat with Royal Oppression's Ignition-like effect. Royal Oppression must already be face-up before Scapegoat is activated in order for Royal Oppression's Ignition-like effect to be used.
  
• Example 2: Player A Tribute Summons Mobius the Frost Monarch and uses its effect to target player B's face-down Skull Lair. Player B could activate his set Skull Lair as a chain to Mobius the Frost Monarch's effect, but he could not use Skull Lair's Ignition-like effect to destroy Mobius the Frost Monarch at the same time. Skull Lair must have already been face-up before Mobius the Frost Monarch was Summoned in order for its Ignition-like effect to be Chained to Mobius the Frost Monarch's effect.
  

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Goat Format Rule #7: Verifying Hands and Decks

Effects that require hands or decks to be revealed in order to ensure that they have resolved correctly must always be carried out, even if knowledge of the games rules or forbidden/limited list already provide you with enough information to verify that they have resolved correctly.

• Example 1: Player A activates Mind Crush, naming D.D. Warrior Lady. Player B has a copy of D.D. Warrior Lady in his graveyard. Even though D.D. Warrior Lady is limited to 1, player B must still reveal his hand to verify that Mind Crush has resolved correctly.
• Example 2: Nobleman of Extermination is activated and banishes Sakuretsu Armor. Both players banish a total of 3 copies of Sakuretsu Armor from their deck. They still must reveal their decks to each other to verify that Nobleman of Extermination has resolved correctly.
  

However, it's worth noting that tournament policy at the time stated that the purpose of checking private information locations was not to memorize the entire contents of the opponent's deck or hand and was to be conducted in a quick fashion so as not to interrupt the flow of the game. When playing Goat Format online, players are able to screenshot each other's decks or hands in order to gain perfect information without anyone knowing, violating the spirit of the rule regarding hand or deck verification. Because of this, when playing online, it has become standard conduct to not verify each other's decks or hands for cards such as Nobleman of Crossout and Mind Crush. Instead, to ensure that these cards have resolved correctly, players can simply use the replays at the end of the match.
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Goat Format Rule #8: Failure to Find

​Cards that search the deck can be used without any legal options. The one weird exception to this rule is The Agent of Creation - Venus, whose effect still requires Mystical Shine Balls in the deck to be used.

• Example 1: Player A discards Thunder Dragon to search his deck for more copies of Thunder Dragon, even though he knows that he has none. The deck is still shuffled afterwards.
• Example 2: Player A activates Reinforcement of the Army and finds that his deck contains no Warrior monsters. The deck is shuffled, and Reinforcement of the Army is placed in the graveyard.
  

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Goat Format Rule #9: The Damage Step and Its Discontents

The Damage Step is notorious in the Yu-Gi-Oh! TCG for its complexity. The rules governing the Damage Step changed many times in subtle ways throughout the history of the TCG, but as far as Goat Format is concerned, you really only need to know the following three things.

9A: Damage Substeps and Distinct Timings
Most of the complexity of the Damage Step arises out of its unique series of distinct timings at which cards and effects can be activated. ​While this vocabulary became antiquated in later years, these were colloquially (and unofficially) referred to as "substeps" in 2005. In current Yu-Gi-Oh!, the Damage Step has five such "substeps" or timings. In Goat Format, on the other hand, there are six:

• Substep 1: Start of the Damage Step
  Some Trigger Effects activate here, before the target of the attack is flipped face-up. Examples include the Trigger Effects of Ninja Grandmaster Sasuke, Mystic Swordsman LV2 and Sasuke Samurai. These effects often state explicitly that they activate and resolve “without flipping [the attack target] face-up or applying damage calculation.” Monster effects that negate activations and Counter Trap cards can be activated here.
• Substep 2: Before Damage Calculation
  The target of the attack is flipped face-up if necessary at the start of this substep. Continuous Effects of the attack target are now active if the attack target was previously face-down. But Continuous Effects that destroy monsters (such as the effect of Berserk Gorilla) will not apply until later (after Damage Calculation). Some cards and Trigger Effects activate here, such as Cross Counter and the effect of Reflect Bounder. Monster effects that negate activations and Counter Trap cards can be activated here.
• Substep 3: Damage Calculation
  The turn player retains priority at the start of this substep to activate certain Trigger Effects; if they have no such effects, the opponent can then activate their own. Then, players may activate other effects that alter the ATK and/or DEF of a monster, monster effects that negate activations, and Counter Trap cards. Examples of effects that activate here include the effects of Kuriboh, Injection Fairy Lily and Sanga of the Thunder. After the resolution of the resulting Chain, determine the results of battle, but do not send monsters destroyed by battle to the Graveyard quite yet.
• Substep 4: After Damage Calculation
  Battle Damage to a player's Life Points is applied at the start of this substep. If a Continuous Effect that destroys monsters came into play back in substep 2, those effects will start to apply now (so Berserk Gorilla, etc. will be destroyed). But if a monster with a Continuous Effect was destroyed by battle, its effect will no longer apply in this substep and onwards. Trigger Effects that activate when a monster inflicts Battle Damage activate here and form a Chain if necessary. Examples of these include the effects of Airknight Parshath, Don Zaloog, White Magical Hat, Masked Sorcerer and Spirit Reaper. Monster effects that negate activations and Counter Trap cards can be activated here.
• Substep 5: Before the end of the Damage Step
  Colloquially referred to as the "resolve effects" substep, this window is devoted entirely to the resolution of Flip Effects and similarly-triggered effects. Flip Effects, other Trigger Effects that activate when a monster is flipped face-up, and many effects that activate “after damage calculation” activate here and form a Chain if necessary. Additionally, many effects that activate "when a monster is destroyed by battle" but before that monster is sent to the Graveyard will activate here. Some examples of effects that activate here include the effects of Apprentice Magician, Helping Robo for Combat, Royal Keeper, Nightmare Penguin, D.D. Assailant, and D.D. Warrior Lady. Monster effects that negate activations and Counter Trap cards can be activated here.
• Substep 6: End of the Damage Step
  Monsters destroyed by battle are sent to the Graveyard at the start of this substep. So as you could probably guess, any effects triggered by destruction by battle will activate in this substep and form a Chain if necessary. Examples include the effects of Mystic Tomato, Last Will and Sangan. Monster effects that negate activations and Counter Trap cards can be activated here.

This can get a little confusing at times. If you're unsure of the timing at which a particular Trigger Effect activates, refer to the appropriate entries in our Individual Rulings pages.

9B: One Shot, Do Not Miss Your Chance to Blow
In current Yu-Gi-Oh!, an unlimited number of Chains can be activated during the Damage Step, in the "before damage calculation" window. These Chains generally involve Spell Speed 2 effects that alter the ATK and/or DEF of a monster. In Goat Format, this works slightly differently; all such "modifiers" must be activated during Damage Calculation, not before it. And only one Chain can occur during Damage Calculation (unless the resolution of one Chain triggers some other effect). So if a player's Spell Speed 2 effect to boost their monster's ATK is negated by a Counter Trap, that player has lost their chance, so to speak, to activate more Spell Speed 2 effects of this kind.

• Example: Player A has his X-Head Cannon attack player B's Airknight Parshath. In the Damage Step, player A activates Limiter Removal. Player B chains Solemn Judgment. The Chain resolves, and X-Head Cannon will be destroyed in battle before player A has the opportunity to activate another Limiter Removal.
  

9C: No Spell Speed 2 Spells or Traps, Monster Effects Only, Final Destination
​In current Yu-Gi-Oh!, barring Trigger Effects and effects with specific rulings to the contrary, players are generally limited in the Damage Step to the activation of three types of effects: Spell Speed 2 effects that directly alter the ATK and/or DEF of a monster, Spell Speed 2 effects that negate activations of cards or effects, and Spell Speed 3 cards. In Goat Format, this is only slightly different: players can only activate monster effects that negate activations, not Quick-Play Spells, Normal Traps, or the effects of Continuous Traps.

• Example: Player A declares an attack with Battle Ox and selects Player B's set Man-Eater Bug as the attack target. When Man-Eater Bug's effect activates before the end of the Damage Step, Player A will not be able to activate My Body as a Shield from their hand in response.

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Goat Format Rule #10: The Match Draw is a Lie

This can be a confusing topic for some people, because the rulebook that was distributed at the time during Goat Format actually contained incorrect information about draws that was not applied in tournaments that were ran during this time.

Although the rulebook stated that a match could end in a draw (e.g. 1 win + 1 loss + 1 draw = 1 match draw), this was not applied at tournaments, as it was literally impossible to enter a match draw into the tournament software. Matches must always be played until one player has won 2 duels.

Goat Format Rule #11: Dude, Where's My Trigger?

In Goat Format, triggers can be recognized as being met in the middle of a Chain, whereas in current format Yu-Gi-Oh! this is generally not the case. Tricks involving moving monsters to a different location to prevent them from triggering will not work in Goat Format. Also, unlike in current Yu-Gi-Oh!, Trigger Effects can be met while the monster is in the deck.

• Example 1: Player A activates Compulsory Evacuation Device, targeting Player B's set Magician of Faith. Player B Chains Desert Sunlight. Desert Sunlight resolves, reveals the Magician of Faith, which the gamestate now recognizes as being triggered. Compulsory Evacuation Devices returns the Magician of Faith to Player B's hand. A new Chain is formed with Magician of Faith's effect as Chain Link 1.
  
• Example 2: Player A activates A Feather of the Phoenix, discarding Night Assailant from their hand and selecting the same Night Assailant as the target for the effect of A Feather of the Phoenix. When this effect resolves, Night Assailant is placed on top of Player A's deck. Then, a new Chain is formed with Night Assailant's effect as Chain Link 1.

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Goat Format Rule #12: Monsters Equipping Monsters

In Goat Format, if a monster like Relinquished or Thousand-Eyes Restrict tries to equip an opponent's monster to itself, and an effect is Chained that causes Relinquished/Thousand-Eyes Restrict to be removed from the field or flipped face-down, the opponent keeps their monster (it is not sent to the graveyard). On the contrary, in current format Yu-Gi-Oh!, the monster would in fact be sent to the Graveyard.

• Example 1: Player A activates the effect of Thousand-Eyes Restrict, targeting Player B's Dark Magician. Player B Chains Book of Moon, targeting Thousand-Eyes Restrict. Book of Moon resolves, flipping Thousand-Eyes Restrict face-down. Then Thousand-Eyes Restrict resolves without effect, and Player B keeps their Dark Magician.
  
• Example 2: Player A activates the effect of Relinquished, targeting Player B's set monster. Player B Chains Raigeki Break, targeting Relinquished. Raigeki Break resolves, destroying Relinquished. Then Relinquished resolves without effect, and Player B keeps their set monster.
  
  

Goat Format Rule #13: A Cure for the Summoning Sickness

In current format Yu-Gi-Oh!, the battle position of a monster can never be changed during the turn that it was Summoned. In Goat Format, there is one weird exception to this rule. If you take control of one of your opponent's monsters, you will always be entitled to your manual battle position even if it was just Summoned that turn. In other words, a monster's position cannot be changed manually if it was Summoned that turn by the turn player. But if a monster is summoned by the opponent of the turn player, its battle position can be changed on the same turn.

• Example 1: Player B activates Scapegoat during Player A's turn. Player A activates Snatch Steal on one of the Sheep Tokens and switches it to Attack Position.
  
• ​Example 2: Player A activates The Shallow Grave, and Player B Special Summons Magician of Faith face-down. Player A activates Mind Control on Magician of Faith and Flip Summons it.

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Goat Format Rule #14: The Other Guys

This one is short and sweet. In current format Yu-Gi-Oh!, when two Attack Position monsters with 0 ATK battle each other, neither one is destroyed. On the contrary, in Goat Format, both monsters are destroyed in battle. This, however, comes up very rarely.

Goat Format Rule #15: Killing Yourself to Live

In current format Yu-Gi-Oh!, if you have a card or effect with an activation cost involving the payment of Life Points (LP) and you have exactly enough LP remaining to pay that cost, you can activate the card or effect, pay all of your remaining LP, and immediately lose the game. In Goat Format, this is not the case; you must have a higher LP total such that you can pay the cost while remaining above 0 LP in order to activate such a card or effect. Similarly, if a card has a mandatory LP maintenance cost, it will not force a player to pay all of their remaining LP in this situation; these cards will simply be destroyed as if the player had less remaining LP than the amount required by the cost. This comes up rarely, but can be relevant with a select few cards that involve maintenance costs, such as Archfiend monsters.

A similar quirk exists with draw effects when the player's Deck has too few cards remaining to fully resolve the effect in question. In current format, you are generally prohibited from activating such effects in these circumstances. But in Goat Format, you can always activate an effect that will deck a player out. This was and remains key for Empty Jar combos, wherein the Empty Jar player will frequently use Card Destruction and Serial Spell to win the game by decking the opponent out.

Goat Format Rule #16: Infinity Wars

The Yu-Gi-Oh! TCG has always enforced special rules and policies for the handling of infinite loops. But like so many other things, these rules and policies have changed throughout the years. In current Yu-Gi-Oh!, when an infinite loop is created, no matter how, a rather nuanced procedure is used wherein players and judges determine which card is the "primary cause" of the loop; that card is then sent to the Graveyard by game mechanics. In Goat Format, this is true for "involuntary" infinite loops, e.g. when an infinite loop is initiated by game mechanics and not by the action of a player. But a voluntary action that would cause an infinite loop is simply illegal. This is best explained by example:

• Example 1: Player A has a Gemini Elf, a Luminous Spark and a Pole Position face-up on the field. Gemini Elf is the monster on the field with the highest ATK, so it is unaffected by Spell Cards. If Player B Summons X-Head Cannon, Luminous Spark will raise its ATK to 2300, making it the highest ATK monster on the field. So X-Head Cannon would become unaffected by Spell Cards, so it would drop to 1800 ATK, then increase to 2300, and so on. This would create an infinite loop. So Player B cannot Summon X-Head Cannon.
• Example 2: Player B has a Blue-Eyes White Dragon and a Pole Position face-up on the field. Player A has a Gemini Elf and an Opticlops equipped with an Axe of Despair face-up on the field, as well as a Set Ring of Destruction. If Player A activates Ring of Destruction to destroy Player B's Blue-Eyes White Dragon, then Opticlops will become the monster with the highest ATK on the field. Then it will become unaffected by Spell Cards, so it will cease to be the monster with the highest ATK on the field, and so on. So Player A cannot target Player B's Blue-Eyes White Dragon with Ring of Destruction.
• Example 3: Player B has a set Pole Position and no other cards. Player A has a face-up Opticlops and a face-up Gemini Elf. Player A activates Axe of Despair, selecting Opticlops as the target. If Player B Chains Pole Position, it will create an infinite loop upon the resolution of Pole Position and Axe of Despair. So Player B cannot Chain Pole Position.
• Example 4: Player A has a Pole Position and an Opticlops face-up on the field. Player B has a Muka Muka equipped with an Axe of Despair face-up on the field with no cards in his hand. Player B draws a card at the start of his turn, making Muka Muka's ATK rise to 1900. Since Muka Muka is now the monster on the field with the highest ATK, it becomes unaffected by the effects of Spell Cards. But once unaffected by the effects of Spell Cards, Muka Muka no longer has the highest ATK on the field. An infinite loop has been created by something that could not be avoided, so Pole Position is destroyed.
  
  

Goat Format Rule #17: State of the Unions

In current Yu-Gi-Oh!, multiple Union Monsters can be equipped to the same legal target at the same time. In Goat Format, this is not the case; a monster can only be equipped with 1 Union monster (through its Union effect) at any given time. Additionally, in Goat Format, most Union monsters can be used to prevent the destruction of the equipped monster by battle, but not by card effects (even where recent errata would suggest otherwise). Since both of these changes were implemented in the current Advanced format through the use of extensive card errata, these issues can get confusing when playing on certain online simulators that display up-to-date card text. But for all intents and purposes, you can assume every Union monster in Goat Format is printed with the "old" type of effect text (with the one-Union-per-monster and destruction-by-battle limitations).