The Battle Phase is the Phase in which battles are conducted. A Battle Phase can be conducted every turn (except for the first turn of the Duel) after the turn player ends their Main Phase 1.
Multiple Battle Phases
"An Unfortunate Report", "Weather Report", and "Last Turn" are the only Cards that can grant multiple Battle Phases in one turn.
If a Monster in attack position attacks or is attacked, its ATK value counts.
If a Monster in defense position is attacked, its DEF value counts.
When two Monsters in attack position battle, the Monster with the higher ATK value wins; if tied both Monsters are destroyed.
If two Monsters battle while the attacked Monster is in defense position and its DEF value equals the ATK of the attacking Monster, both Monsters stay on the field.
The Battle Phase is split into four steps:
Damage Step (including damage calculation)
The Start Step, Battle Step, and End Step always occur during every Battle Phase, unless skipped due to a Card Effect. The Damage Step only occurs if a Monster's attack is successful, up to the point where both players agree to leave the Battle Step. If a Card Effect ends the Battle Phase (such as "Battle Fader"), it immediately becomes the End Step, unless the Card Effect changes the Phase directly (such as "Neko Mane King"), in which case it is no longer the Battle Phase.
During the Damage Step only Cards with the following Effects can be activated:
- Spell Speed 2 Effects that alter ATK or DEF
- Mandatory Effects
- Counter Trap Cards
- Monster and Trap Effects that negate the activation of a Card or Effect.
- Trigger and Trigger-like Effects: if that Effect activates in response to the Card itself being moved to a different location, being flipped face-up (including Flip Effects), or having its battle position changed
Entering the Battle Phase
You do not need to control any Monsters in order to enter your Battle Phase. Even if their opponent controls no valid attack targets (e.g. if the opponent only controls two face-up copies of "Dupe Frog" you may still enter your Battle Phase.
Entering your Battle Phase is optional after your Main Phase 1 ends, except when Card Effects mandate it. For example, the turn player must enter the Battle Phase if a Card Effect is forcing a Monster(s) they control to attack during that turn, even if another Card Effect is currently preventing them from attacking, such as a face-up "Gravity Bind". If you do not choose to enter your Battle Phase after your Main Phase 1 ends, you must proceed immediately to the End Phase, without entering your Main Phase 2.
Skipped Main Phase 1
If a Card Effect skips your Main Phase 1, such as that of "Timeater", you do not have to enter your Battle Phase from your Standby Phase, you may choose to enter your End Phase instead.
However, if Card Effects skip your Main Phase 1 and Battle Phase during the same turn, you cannot enter your Main Phase 2 and must instead proceed immediately to your End Phase.