The combat showdown

When combat begins, it opens with a showdown of its own, the Combat Showdown, or turns a showdown already running at that battlefield into one.¹Rule 464.2. When Combat opens, it either opens with a Combat Showdown, or the current Showdown becomes a Combat Showdown. Open in the rules browser The window is the one Track 1 described: players may play cards and activate abilities with Action or Reaction,²Rule 316.8.c. A Showdown is a structured Window of Opportunity where Players may play cards and activate abilities with Action or Reaction. See rule 341. Showdowns for more information. Open in the rules browser and nothing else may be played or activated while it runs.³Rule 308.1.a. Only cards and abilities with the Action or Reaction keywords can be played or activated in a Showdown State. Open in the rules browser No unit may take a Standard Move until combat is over.⁴Rule 144.1.c. This action cannot be performed during a Showdown or Combat. Open in the rules browser

As combat opens, effects that happen at the start of a combat or showdown take place,⁵Rule 464.2.b. 1. Start of combat or showdown effects happen now. Open in the rules browser and then the Attacker and Defender are established.⁶Rule 464.2.c. 2. Establish who is Attacker and who is Defender. Open in the rules browser Moving does not use the chain, so your opponent could not react to your move itself.⁷Rule 446.3.c. Moving does not use the Chain, nor is it able to be Reacted to. Open in the rules browser Their chance to answer comes in the showdown that follows.

Who acts, and when

Two terms first. The turn is in a Showdown Open State when a showdown or combat is in progress and nothing is on the chain.⁸Rule 310.3. Showdown Open: A Showdown or Combat is in progress and no Chain exists. Open in the rules browser Focus is the permission to take appropriately timed actions while the turn is in that state.⁹Rule 313.1. Focus is the permission to take appropriately timed Discretionary Actions when the turn is in a Showdown Open State. See rule 307. States of the Turn for more information. Open in the rules browser When combat opens a new showdown, the Attacker gains Focus as it begins.¹⁰Rule 464.2.c.1.a. If a showdown opens as part of combat, this player gains Focus as the showdown begins. Open in the rules browser A player who gains Focus also gains Priority,¹¹Rule 313.2. A player who gains Focus also gains Priority. Open in the rules browser and Priority is the exclusive right to take those actions.¹²Rule 312.1. Priority is the singular exclusive right to take Discretionary Actions. See rule 410.1. Discretionary Actions for more information. Open in the rules browser How Priority moves while a chain is open is covered later, with timing.

The player with Focus does one of two things. They may play a card or activated ability that is legally timed¹³Rule 347.1. Play a Card or Activated Ability that is legally timed. Open in the rules browser, which starts a chain as normal,¹⁴Rule 347.1.a. The card or activated ability will start a Chain as normal. Open in the rules browser and when that chain closes, Focus passes to the next player in turn order.¹⁵Rule 347.1.b. When that Chain closes, Focus passes to the next Player in Turn Order. Open in the rules browser Or they may pass.¹⁶Rule 347.2. Pass. Open in the rules browser If every player has passed once in sequence, the showdown ends;¹⁷Rule 347.2.a. If all Players have passed once in sequence, the Showdown ends. Open in the rules browser otherwise Focus passes to the next player in turn order.¹⁸Rule 347.2.b. Otherwise, Focus passes to the next Player in Turn Order. Open in the rules browser

In a showdown, legally timed means Action or Reaction. A card with Action may be played during showdowns, even when it is not its controller's turn.¹⁹Rule 806.1.b. Action grants the corresponding card or effect permission to be played or activated during Showdowns, even when it is not the Controlling player's turn. Open in the rules browser A card with Reaction has every permission Action gives,²⁰Rule 813.1.b. Reaction grants the corresponding card or effect all abilities and permissions of Action. Open in the rules browser and it can also be played during a Closed State on any player's turn.²¹Rule 813.1.c.1. On Cards: "This can be played during Closed States on any player's turn." Open in the rules browser The turn is in a Closed State whenever a chain exists,²²Rule 309.1. If a Chain exists, the turn is in a Closed State. Open in the rules browser and only cards and abilities with Reaction can be played or activated then.²³Rule 309.1.a. Only cards and abilities with the Reaction keyword can be played or activated in a Closed State. Open in the rules browser So a card with Action waits for your Focus, and a card with Reaction can also answer something that is already on the chain.

How it closes

If all players pass Focus without playing a spell or activating an ability, the showdown closes.²⁴Rule 348. If all players pass Focus without playing a spell or activating an ability, then the Showdown Closes. Open in the rules browser This is where combat parts ways with Track 1. A non-combat showdown closes by settling control: if only one player's units remain and that player does not already control the battlefield, they establish control.²⁵Rule 348.2.a. If only one player’s Units remain at the Battlefield, and if that player does not already Control the Battlefield, that player establishes Control over the Battlefield. See rule 188. Control for more information on Control. See rule 469.1. for more information on Conquering. Open in the rules browser A Combat Showdown settles nothing yet. Combat proceeds with its remaining steps instead,²⁶Rule 348.1. If it is a Combat Showdown, proceed with the remaining steps of Combat to resolve the phase. See rule 463. The Steps of Combat for more information. Open in the rules browser and control of the battlefield still cannot change until one of those steps says so.²⁷Rule 190.4.b. While a Combat or Showdown is ongoing at a Battlefield, Control of that Battlefield cannot change until instructed by steps of the Combat or Showdown. Open in the rules browser

The first of those steps is combat damage. If units from both sides are still at the battlefield when the showdown closes, attackers and defenders resolve combat damage there.²⁸Rule 465.2. 1. When the Showdown closes, Attackers and Defenders resolve Combat Damage at the Battlefield that was attacked, using their current Might. Open in the rules browser