Battle Phase is the fourth Phase in a turn, and can be entered each turn except for the first turn. In the battle phase, you can declare attacks. If there are no monsters on the opponent's side of the field, a direct attack can be declared, inflicting damage equal to the monster's ATK points.
The Battle Phase is divided into four steps:
 Start step
The start step is the declaration of entering the battle phase. Either player can activate card effect(s) during the start step in response to the entering of the battle phase.
 Battle step
The battle step is initiated when an attack is declared. During this time, card effects can be activated in response to the attack, such as Mirror Force
 Damage step
If no cards are activated in response during the battle step, the Damage Step is where Damage Calculation is occurred. During the damage step, only certain card effects may be activated:
- Effects which alter the attack or defense of a monster
- Quick effects that negate an effect(s)
- an effect that states will occur doing the damage step
- Mandatory effects
- Flip monster effects (Which are mandatory)
- Counter trap cards
Cards that special summon during the Damage Step cannot be negated by card effects such as Bottomless Trap Hole, since these cards cannot be activated in the damage step. Additionally, cards such as Royal Decree cannot be activated in response due to their inability to be used in the damage step.
 End step
The End step is the declaration that the Battle Step has ended. Here, effects that activate "At the end of the battle phase" such as Gladiator Beast monsters will activate. Additionally, either player may activate a card effect which has a Spell Speed of 2 or higher at the end step.