In the trading card game, players draw cards from their respective decks and take turns playing cards onto "the field". Each player uses a deck containing forty to sixty cards, and an optional "extra deck" of up to fifteen cards. There is also an optional fifteen-card side deck, which allows players to swap cards from their main deck and/or extra deck between games. Players are restricted to three of each card per deck and must follow the Forbidden/Limited card list, which restricts selected cards by Konami to be limited to two, one, or zero. Each player starts with 8,000 "life points" (LP) (Though the players can decide to start with more or less in casual games), with the main aim of the game to use monster attacks (and sometimes card effects) to reduce the opponent's life points. The game ends upon reaching one of the following conditions:

• A player loses if their life points reaches zero. If both players reach zero life points at the same time, the game ends in a draw.
• A player loses if they are required to draw a card, but have no more cards to draw in the main deck.
• Certain cards have special conditions which trigger an automatic win or loss when its conditions are met (e.g. having all five cards of Exodia the Forbidden One in the hand, playing all five cards of the Destiny Board on the field, or having Ghostrick Angel of Mischief on the field with ten XYZ materials).
• A player can forfeit at any time.

Cards are laid out in the following manner:

• Main Deck: The player's main deck is placed here face-down, and can consist of 40 to 60 cards. Normal, Effect, Ritual, and Pendulum monsters can be stored here. Spell and Trap cards are also stored here.
• Extra Deck: The player's extra deck is placed here face-down, if they have one, and may have 15 cards consisting of Fusion, Synchro, Xyz, and Link monster cards. Pendulum monsters are also placed here face-up when they would otherwise be sent from the field to the Graveyard.
• Graveyard (GY): A zone where cards are sent to when they are discarded or destroyed, like monsters that have been tributed or destroyed, or most spell/trap cards after they have been activated.
• Main Monster Zones: A field of five spaces where monster cards are placed when successfully Summoned. Prior to the addition of Link monsters, any kind of monster could be placed there at any time. After Link monsters were introduced, monsters from the extra deck could only be Special Summoned from the extra deck to the extra monster zone, or a main monster zone a Link monster points to, up until the rule change for April 2020 onward, where only Link monsters and Pendulum monsters summoned from the extra deck follow this restriction.
• Extra Monster Zones: Introduced with Link monsters, this is a zone where monsters from the extra deck can be Summoned. An extra monster zone is not a part of either player's field until they Summon a monster to the extra monster zone, meaning they are shared between the players.
• Spell/Trap Zones: Five spaces in which either spell or trap cards can be placed. The leftmost and rightmost spell/trap zones can optionally be treated as "Pendulum zones" by placing Pendulum monsters there, allowing players to use Pendulum effects and perform Pendulum Summons.
  • The Pendulum Zones originally were at the left and right sides of the main monster and spell/trap zones when introduced with the Arc-V era, but were integrated into the leftmost and rightmost spell/trap zones during the VRAINS era.
• Field Zone: A zone where field spell cards are placed.
• Banishment: A zone where cards that are "banished" by card effects are sent.

Each player's turn contains six phases that take place in the following order:

• Draw Phase: The turn player draws one card from their deck.
• Standby Phase: No specific action occurs, but it exists for card effects and maintenance costs that activate or resolve during this specific phase.
• Main Phase 1: The turn player may Normal Summon or Set a monster, activate cards and effects that they control, change the battle position of a monster (provided it was not summoned this turn), and Set Spells or Traps face-down.
• Battle Phase: The turn player may choose to attack their opponent using any monsters on their field in Attack Position. Depending on the position of opposing monster, the attacking monster's ATK points are taken into account against the opposing monster's ATK or DEF points. If both monsters are in Attack Position, the monster with fewer ATK points is destroyed and its owner takes life point damage equal the difference between both monster's ATK points (if both monsters have equal ATK points, they are both destroyed and no damage is taken, unless both of their ATK points are 0, in which case neither is destroyed). If the opposing monster is in Defense Position and has fewer DEF points than the attacking monster's ATK points, it is destroyed and the owner takes no damage. However, if its DEF point is equal or higher, the attacker takes life point damage equal to the difference between the two values and neither monster is destroyed. If the defending player has no monsters defending them, a Direct Attack can be performed, with the defending player receiving life point damage equal to the attacking monster's ATK points. The turn player can choose to not enter the battle phase and instead go to the end phase.
• Main Phase 2: The player may do all the same actions that are available during main phase 1, though they cannot repeat certain actions already taken in main phase 1 (such as Normal Summoning) or change the battle position of a monster that has already been summoned, attacked, or had their battle position changed during the same turn. This phase is only accessible if the battle phase was entered.
• End Phase: The player declares the end of their turn. Certain card effects and maintenance costs may activate or resolve during this specific phase.

At the start of a game, the starting player cannot enter the draw or battle phases during their first turn.

Gameplay revolves around three types of cards: monster, spell, and trap cards. Monster cards are monsters used to attack and defend against the opposing player, mainly for the purpose of damaging an opponent's life points. Spells, which can either be played from the hand or set for later use, provide various effects such as altering a monster's strength, drawing additional cards, or removing an opponent's cards from the field. Traps are cards that are set on the field in advance and activated in later turns when certain conditions are met, such as when an opponent targets a player's monster.

With some exceptions, a typical monster card possesses ATK and DEF points that determine its attack and defense power in battles, a level represented by stars, with more powerful monsters typically being of higher levels, an attribute that certain effects may react to, and a description listing the monster's types and any effects or summoning conditions they may have. Monsters are summoned to the field through three main categories of summoning: Normal, Tribute, and Special. Once during a player's main phase, they can choose to normal summon a level 4 or lower normal or effect monster from their hand, in face-up attack position or face-down defense position, or tribute summon a level 5 or higher monster by tributing one or more monsters already on the field. Special summons are performed by utilising card effects or fulfilling the conditions of other summoning methods, such as those used to summon cards from the extra deck, and may be performed as many times as desired if the conditions are met.

The game currently features the following types of monster.

• Normal (yellow): A monster with no effects of its own, instead simply having a description of the monster. Stored in the main deck and can be normal, tribute, or special summoned. Due to their lack of a effect, they are rarely played in the modern competitive game, unless there is an archetype (a series of thematically related cards that support each other) that centers on a particular normal monster; an example would be the Dark Magician archetype.
• Effect (orange): A monster that possesses at least one effect. Can be summoned in the same manner as normal monsters.
• Ritual (blue): Stored in the main deck, these monsters can typically only be special summoned by using a ritual spell card and tributing required monsters listed in its instructions that meets the ritual monster level or is greater then its level its level.
• Fusion (purple): Stored in the extra deck, these monsters are summoned by utilising cards with a "fusion" effect, such as the Spell Polymerization, and Using monsters listed in the monster's description. Another mechanic Fusion monsters possess is the ability to fusion summon without a spell card, they are instead summoned by following the requirement for the monster materials written on the card.
• Synchro (white): Stored in the extra deck, these monsters are summoned by using from the field a tuner-type monster and one or more non-tuner-type monsters whose levels equal the level of the synchro monster being summoned.
• Xyz (black): Stored in the extra deck, these monsters possess ranks as opposed to levels, and require two or more monsters whose level is the same as the Xyz monster's rank. These monsters become the Xyz monster's "overlay units", which can then be sent to the GY by "detaching" them to activate effects. Besides the usual Xyz summon, some monsters can be summoned by using a Rank Up Magic/Rank Down Magic Spell card (which summons a Xyz monster of a higher or lower rank than the one that was Used) or by their effect, bypassing the usual summoning requirements.
• Pendulum (green gradient): Variations of other monster types which, if sent from the field to the GY, are placed face up in the extra deck instead. Pendulum monsters can be placed in pendulum zones in the leftmost and rightmost spell/trap zones, where they can utilise pendulum effects. When both pendulum zones contain pendulum monsters with differently valued "pendulum scales", players can perform a pendulum summon during the main phase to summon multiple monsters from the hand and face-up pendulum monsters from the extra deck whose levels lie between the two pendulum scale values.
• Link (dark blue): Stored in the extra deck, link monsters have link values instead of levels and can only be played in attack position. These are summoned by using one or more monsters on the field as link material that meets the summon requirements, with link monsters able to be used as multiple link material depending on its link value. Link monsters feature arrows which, when pointed towards other zones on the field, allows additional link monsters to be summoned outside of the extra monster zone to the zone those link monsters point to. Link monsters may also possess effects that can be used when another card is Co-linked.
• Token (grey): A low-level monster that can only be summoned through card effects. These cards do not exist outside of the field and are removed from play upon leaving. While official token monster cards do exist, players can use other objects such as coins to represent token monsters.

Also there are subtype monsters with special effects being;

• Flip: Flip monsters have the unique mechanic to use effects when they are turned face-up.
• Union: Union monsters have the unique mechanic to equip or unequip from a monster.
• Gemini: Gemini monsters have the unique mechanic to normal summon while on the field to gain additional effects.
• Toon: Toon monsters have the unique mechanic to attack directly if your opponent has no toon monsters.

Spell cards, green, are magical spells with a variety of effects, such as reviving destroyed monsters. They can be played from the hand during a player's turn or placed faced down for activation on a later turn. There are six types of Spell Card:

• Normal: A spell that can only be activated during the player's main phase.
• Quick Play: A spell that can be activated from the hand at any time during the player's turn, or can be set and activated during an opponent's turn. However, they cannot be activated the turn they are set.
• Continuous: A spell with a continuous effect that remains until conditions are met or it is destroyed.
• Equip: A spell that is equipped to a monster, providing it with support effects. It is removed if the monsters leaves the field or is set face-down, or the card is destroyed.
• Field: A spell that is placed in a player's field spell zone, which affects the entire field. Each player can only have one field spell in play at a time.
• Ritual: A spell that is required to summon a ritual monster.

Trap cards, dark pink, have to be set on a player's field face-down and can only be activated after the turn they were set has passed, including the opponent's turn. (Quick play spells, when set, have the same rule.) They are generally used to stop or counter the opponent's moves, and come in three varieties.

• Normal: A standard trap that is discarded once its effect resolves.
• Continuous: A trap that remains on the field until destroyed or its conditions are met.
• Counter: A trap that is activated in response to the activation of other cards.

A chain is a stack of card effects activated one after the other. It exists for the management of multiple card effects.

A chain is created when the effects of One or more card are activated at the same time, or when a player activates an effect after a card is played, but before the card impacts the game.

If the effect of a card is activated, the opponent always has the possibility to reply with an effect of their own cards.

• If the opponent replied with an effect, the player can choose to reply back and add another effect to the chain.
• If the opponent chooses not to reply, the player can add a second effect and create a chain off of the activation of their own card. Mandatory effects must be activated before or at the start of chain or right after the chain resolves.

Each player can then continue to add effects to the chain. The chain ends when the players wish to not play any more cards. Should this happen, the chain is resolved: the resolution is performed in reverse order of play, starting with the effect of the most recently played card.

It is advised to not resolve card effects before ensuring that a chain had not been created.(ask for a Response)

The player plays Raigeki (a normal spell destroying all of the opponent's monsters) (Starting Chain link 1). As a response to the player’s Raigeki, their opponent plays Destruction Jammer (a counter trap that negates the destruction of a monster by discarding a card) to negate the effects of Raigeki (thus placing Destruction Jammer in chain link 2). The player then plays Solemn Judgement (a counter trap that negates a monster summon and/or the activation of a spell or trap, but at the cost of half of the player's LP) (as chain link 3 to negate Destruction Jammer's effect). Their opponent decides not to reply to Solemn Judgement, thus the chain is resolved starting with the highest chain link, which achieves this result:

1. Solemn Judgement is activated: the player pays half of their LP, and the effect of destruction jammer is negated.
2. Destruction Jammer should have been resolved and negate the effect of Raigeki, but Solemn Judgement prevents the effect from resolving.
3. Raigeki is then able to resolve successfully, and all of the opponent's monsters are destroyed.

A chain can only be created when a card or effect is activated. Summoning or tributing a monster, changing position or paying a cost do not represent valid effects. Thus, it is not possible to reply to a chain with these effects.