Rules 400

Rules 117

The player with priority may cast spells, activate abilities, and take special actions. A player may cast an instant spell any time they have priority. A player may cast a non-instant spell during their main phase any time they have priority and the stack is empty. A player may activate an activated ability any time they have priority. A player may take some special actions any time they have priority. A player may take other special actions during their main phase any time they have priority and the stack is empty. A player may activate a mana ability whenever they have priority, whenever they are casting a spell or activating an ability that requires a mana payment, or whenever a rule or effect asks for a mana payment.

• The active player receives priority at the beginning of most steps and phases, after any TBA have been dealt with and abilities that trigger at the beginning of that phase or step have been put on the stack. No player receives priority during the untap step. Players usually don’t get priority during the cleanup step.
• The active player receives priority after a spell or ability (other than a mana ability) resolves.
• If a player has priority when they cast a spell, activate an ability, or take a special action, that player receives priority afterward.
• If a player has priority and chooses not to take any actions, that player passes. If any mana is in that player’s mana pool, they announce what mana is there. Then the next player in turn order receives priority.
• If all players pass in succession, the spell or ability on top of the stack resolves or, if the stack is empty, the phase or step ends.

Rules 506 – 511

The combat phase consists of five steps: beginning of combat, declare attackers, declare blockers, combat damage, and end of combat. Throughout this phase, the active player is the attacking player.

Beginning of combat:

in a 2-player game, the non-active player becomes the defending player, then the active player gets priority

Declare attackers:

the attacking player declares their attackers and then gets priority. The declare blockers and combat damage steps are skipped if no creatures are declared as attackers or put onto the battlefield attacking.

Declare blockers:

the defending player declares their blockers. Then the active player announces their damage assignment order for each creature that’s become blocked, and then the defending player chooses their damage assignment order for each blocking creature. The active player then gets priority.

Combat damage:

first, the active player announces how each attacking creature assigns its combat damage, then the defending player announces how each blocking creature assigns its combat damage. Second, all combat damage that’s been assigned is dealt simultaneously (creatures with lethal damage marked on it or with zero power are put into their owner’s graveyards). Then, the active player gets priority. There are two combat damage steps if any attacking or blocking creature has first strike or double strike.

End of combat:

the active player gets priority. Abilities that trigger “at end of combat” trigger as the end of combat step begins. Effects that last “until end of combat” expire at the end of the combat phase.

Side note:

difference between damage assignment order and assigning damage. Imagine AP attacks with a 3/3 with trample and deathtouch. NAP blocks this creature with two 2/2 creatures (let’s call them X and Y). The damage assignment order that happens on the declare blockers step is simply saying “X will be first and Y will be second”. Then, when damage is assigned on the combat damage step, it’s saying “My creature deals 1 damage to X, 1 to Y and 1 to NAP” or “My creature deals 3 damage to X”, for example. Then damage is dealt.

Rule 601

To cast a spell is to take it from where it is (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. The following steps must be done in order:

Announce

To propose the casting of a spell, a player first moves that card from where it is to the stack;

Choose modes

If the spell is modal, the player announces the mode choice. If the player wishes to splice any cards onto the spell, they reveal those cards in their hand. If the spell has alternative or additional costs that will be paid as it’s being cast such as buyback or kicker costs, the player announces their intentions to pay any or all of those costs. A player can’t apply two alternative methods of casting or two alternative costs to a single spell. If the spell has a variable cost that will be paid as it’s being cast (such as an {X} in its mana cost), the player announces the value of that variable. If a cost that will be paid as the spell is being cast includes hybrid mana symbols, the player announces the nonhybrid equivalent cost they intend to pay. If a cost that will be paid as the spell is being cast includes Phyrexian mana symbols, the player announces whether they intend to pay 2 life or the corresponding colored mana cost for each of those symbols.

Choose targets

The player announces their choice of an appropriate object or player for each target the spell requires.

Divide

If the spell requires the player to divide or distribute an effect among one or more targets, the player announces the division. Each of these targets must receive at least one of whatever is being divided.

Check legality

The game checks to see if the proposed spell can legally be cast.

Calculate costs

The player determines the total cost of the spell. 

Activate mana abilities

If the total cost includes a mana payment, the player then has a chance to activate mana abilities. Mana abilities must be activated before costs are paid.

Pay costs

The player pays the total cost in any order.

Then, effects that modify the characteristics of the spell as it’s cast are applied, then the spell becomes cast. Any abilities that trigger when a spell is cast or put onto the stack trigger at this time. If the spell’s controller had priority before casting it, they get priority.

Rule 603

Triggered abilities have a trigger condition and an effect. They are written as “[When/Whenever/At] [trigger condition or event], [effect].”. When a phase or step begins, all abilities that trigger “at the beginning of” that phase or step trigger. Once an ability has triggered, its controller puts it on the stack as an object that’s not a card the next time a player would receive priority. If multiple abilities have triggered since the last time a player received priority, each player, in APNAP order, puts triggered abilities they control on the stack in any order they choose.

• If multiple abilities have triggered since the last time a player received priority, each player, in APNAP order, puts triggered abilities they control on the stack in any order they choose.
• If a triggered ability is modal, its controller announces the mode choice when putting the ability on the stack. If one of the modes would be illegal that mode can’t be chosen. If no mode is chosen, the ability is removed from the stack.
• The remainder of the process for putting a triggered ability on the stack is identical to the process for casting a spell listed in rules.
• If a choice is required when the triggered ability goes on the stack but no legal choices can be made for it, or if a rule or a continuous effect otherwise makes the ability illegal, the ability is simply removed from the stack.

Intervening “if” clause

a triggered ability may read “When/Whenever/At [trigger event], if [condition], [effect].” When the trigger event occurs, the ability checks whether the stated condition is true. The ability triggers only if it is; otherwise it does nothing. If the ability triggers, it checks the stated condition again as it resolves. If the condition isn’t true at that time, the ability is removed from the stack and does nothing. 

Optional triggers

Contain the word “may”. These abilities go on the stack when they trigger, regardless of whether their controller intends to exercise the ability’s option or not. The choice is made when the ability resolves.
There are also other types of triggered abilities: zone-change triggers, delayed triggered abilities, state triggers and reflexive triggers. These kinds of triggers are explored more in depth in this chapter.

Rules 512 – 514

The ending phase has 2 steps: end and cleanup.

Once the end step begins, AP gets priority. If a permanent with an ability that triggers “at the beginning of the end step” enters the battlefield during this step, that ability won’t trigger until the next turn’s end step. Likewise, if a delayed triggered ability that triggers “at the beginning of the next end step” is created during this step, that ability won’t trigger until the next turn’s end step.

Once the cleanup step begins, the two respective TBAs happen in order. Usually, no players get priority during the cleanup step, but if triggers are put onto the stack during this step, players get priority and another cleanup step occurs afterwards – i.e AP discards a card with Madness to get to the maximum hand size, the trigger goes on the stack and they can choose to cast it. When the stack is empty again and all players pass in succession, a new cleanup step occurs.

Rule 703

Turn-based actions are game actions that happen automatically when certain steps or phases begin, or when each step and phase ends. Turn-based actions don’t use the stack and are not controlled by any player. Whenever a step or phase begins, the corresponding turn-based actions are automatically dealt with first. This happens before state-based actions are checked, before triggered abilities are put on the stack, and before players receive priority. The TBAs are, in turn order:

Rule 704

State-based actions are game actions that happen automatically whenever certain conditions (listed below) are met. State-based actions don’t use the stack, are checked throughout the game and are not controlled by any player. Whenever a player would get priority, the game checks for any of the listed conditions for state-based actions, then performs all applicable state-based actions simultaneously as a single event. All of them are described in this chapter, but the most common are:

• If a player has 0 or less life, that player loses the game.
• If a player attempts to draw a card from a library with no cards in it, that player loses the game.
• If a player has ten or more poison counters, that player loses the game.
• If a token is in a zone other than the battlefield, it ceases to exist.
• If a creature has toughness 0 or less, it’s put into its owner’s graveyard. Regeneration can’t replace this event.
• If a creature has toughness greater than 0, it has damage marked on it, and the total damage marked on it is greater than or equal to its toughness, that creature has been dealt lethal damage and is destroyed. Regeneration can replace this event.
• If a creature has toughness greater than 0, and it’s been dealt damage by a source with deathtouch since the last time state-based actions were checked, that creature is destroyed. Regeneration can replace this event.
• If a planeswalker has loyalty 0, it’s put into its owner’s graveyard.
• If a player controls two or more legendary permanents with the same name, that player chooses one of them, and the rest are put into their owners’ graveyards.
• If an Aura is attached to an illegal object or player, or is not attached to an object or player, that Aura is put into its owner’s graveyard.
• If a permanent has both a +1/+1 counter and a -1/-1 counter on it, N +1/+1 and N -1/-1 counters are removed from it, where N is the smaller of the number of +1/+1 and -1/-1 counters on it.

Rule 613

The layers are applied when we have multiple continuous effects on the battlefield:

• Layer 1: Rules and effects that modify copiable values.
  • Layer 1a: Copy effects and merging permanents.
  • Layer 1b: Face-down spells and permanents. They have no characteristics other than those listed by the ability or rules that allowed the spell or permanent to be face down.
• Layer 2: Control-changing effects
• Layer 3: Text-changing effects
• Layer 4: Type-changing effect, including card type, subtype, and/or supertype.
• Layer 5: Color-changing effects.
• Layer 6: Ability-adding effects, keyword counters, ability-removing effects, and effects that say an object can’t have an ability.
• Layer 7: Power– and/or toughness-changing effects are applied.
  • Layer 7a: CDA
  • Layer 7b: Set
  • Layer 7c: Modify
  • Layer 7d: Switch

Within layers 2-6, apply CDA first, then abilities in timestamp order (unless dependency applies). Within each sublayer on layer 7, apply effects in timestamp order, unless dependency applies. This is continually, automatically and instantaneously performed by the game.

The most known multiplayer formats are:

 Team Constructed

(also known as Team Trios), where teams of three players compete in different formats against other teams. Some common setups include Standard/Modern/Legacy, Standard/Pioneer/Modern, Pioneer/Modern/Legacy, and Modern/Legacy/Vintage. Each player plays an individual format and can receive advice from teammates during matches.

Team Unified Constructed

is similar, but all players on a team play the same format, with the unified construction rule prohibiting repeated cards between team decks.

Team Sealed Deck

involves teams of three players building three decks from a large number of booster packs, with each card assigned to a player. Players compete individually against players from the opposing team.

Team Booster Draft

sees two teams of three players drafting and building individual decks to compete.

Two-Headed Giant

is a unique modification where two teams of two players share a turn and can play in any format, be it Constructed or Limited.

Commander

The Commander format accommodates four players with 99 cards plus 1 commander card per deck. Each player selects a legendary creature as their commander and constructs a deck around its color identity and abilities. Decks may include cards from Magic’s history, with a single copy allowed for each card except basic lands. Color identity is determined by mana symbols on cards. Commanders start in the command zone and can be cast from there, with an additional two mana cost per prior casting. If a commander would leave the battlefield, it can return to the command zone. Losing conditions include receiving 21 or more combat damage from a single commander. Players starting at 40 life, commanders in the command zone, and drawing seven cards. Turns progress clockwise, and players can attack any opponent and target any player with spells and abilities. Commander offers strategic gameplay and deck-building creativity. More information is available at https://mtgcommander.net/.