...Cause I'm sure you would love to be fired before having to deal with the Damage Step.
The Damage Step is the most obscure mechanic in the whole game, having many rules that we don't fully understand and others that we maybe haven't figured out yet. It brings up exceptions, special rules, restrictions, and, as expected, some tasty contradictions. This step is one of the steps of the Battle Phase. The Battle Phase itself isn't complicated at all, and it's explained in the Rulebook in a very brief and tidy way. Entering and exiting the Battle Phase is no more complicated than moving in or out of other Phases. The problems start as soon as you declare an attack, and in a game based on monsters battling each other, this is bound to happen sooner or later. We'll be looking at the Battle Step and the Damage Step. Before starting, you can think of these steps as the Phases of a turn. Priority is retained by the turn player, as usual. In some cases, players have to agree to move into the next Step by passing priority, and in other cases, this is done automatically.
The Battle Step is much simplier than the Damage Step. It is composed of two Sub-Steps: The Attack Declaration, and "Before the Damage Step". At the Attack Declaraction Sub-Step, you can activate Cards that respond to an attack's declaration (such as Mirror Force or Magic Cylinder), as well as any other elligible Spell Speed 2 or higher effect (such as Book of Moon or Compulsory Evacuation Device). Only one chain can respond to the attack's declaration, so if you activate Mirror Force, and it is negated, you cannot activate Magic Cylinder in a new chain. Once the single chain that responds to the Attack Declaration is over, gameplay proceeds to the Battle Step. During the Battle Step, any Spell Speed 2 or higher event can be activated, and any number of chains can be manually started. You can no longer activate Cards that respond to the attack declaration, but you can still activate Cards like Book of Moon or Compulsory Evacuation Device. Once both players pass priority, implying that they don't want to start any more chains, gameplay proceeds into the Damage Step.
Some notes about the Damage Step: Its structure has been modified quite a few times through the years. It probably won't stay the same in the future, and currently, it is still different between the TCG and the OCG. In general, everyone agrees that the Damage Step is composed of several Sub-Steps. The differences lay on what each person considers that happens on a Sub-Step, and consequently, how many of them are there. In this article, I'll be using the last official chart that the TCG has received, which consists of seven Sub-Steps. For example, the current OCG chart has more Sub-Steps. In spirit, they work exactly the same. You may have heard the phrase "Sub-Steps no longer exist", which is heavily out of context. The phrase asked to stop reffering to Sub-Steps by their number (such as "Sub-Step 5"), instead of asking to stop treating the Damage Step as a group of Sub-Steps.
The current TCG chart goes like this:
-Start of the Damage Step
-Flipping a face-down monster face-up
-Before Damage Calculation
-After Damage Calculation
-End of the Damage Step
There are some heavy restrictions on which Cards can and cannot be activated during the Damage Step:
-Any Counter Trap Cards (through the entire Damage Step). Examples are Divine Wrath or Dark Bribe.
-Spell Speed 2 effects that modify the ATK/DEF of a monster (from the "Start of the Damage Step" Sub-Step, until the "Before Damage Calculation" Sub-Step included). For example, Limiter Removal or Mirror Wall.
-Effects that specify that they are activated during the Damage Step. For example, Mystic Tomato or X-Saber Airbellum, at their corresponding Sub-Step.
-Quick Effects that negate the activation of other effects (through the entire Damage Step). For example, Gladiator Beast Heraklinos or Stardust Dragon.
-Six particular Cards whose rulings have always allowed them to be activated during the Damage Step, even though they don't meet any of th above categories. They are Attack and Receive, Chthonian Blast, Desrook Archfiend, Michizure, Null and Void, and Numinous Healer. They can only be activated during their corresponding Sub-Steps.
These rules clearly ban a lot of Cards from being activated during the Damage Step, such as My Body as a Shield or Waboku. Now, let's take a look at what happens in each Sub-Step:
The first Sub-Step is the "Start of the Damage Step". At this point, an attacked face-down monster is still face-down. Here, you start applying Continuous ATK/DEF modifiers that apply during the Damage Step, such as Jain, Lightsworn Paladin, or Turbo Warrior. Effects that affect the attacked monster "without flipping it face-up" are activated at this point, such as Neo-Spacian Grand Mole or Mystic Swordsman LV2. Finally, effects that affect the attacked monster based on a certain value of that monster are also activated at this point if the monster is face-up, such as Ally of Justice - Catastor (looks for an Attribute) or Exploder Dragonwing (looks for an ATK value). These are the main type of effects applied at this point. Players rarely use this Sub-Step for any other effects.
The second Sub-Step is the "Flip a face-down monster face-up" Sub-Step. Flipping a face-down monster is the first thing you do during this Sub-Step, and pretty much the only thing you are going to do anyway. There are no effects that specifically activate or start applying at this Sub-Step. If the face-down monster has a Continuous Effect, it starts applying at this point (such as Jinzo). Effects like Catastor or Dragonwing will not activate at this point if they "find out" that the face-down monster meets their requirement. In essence, this is a "mute" Sub-Step, where the most important action is flipping the monster face-up in order to proceed with the next Sub-Steps properly. It makes things tidier. There are two important things to notice, though. The first one is that if a monster has a Continuous Effect to destroy itself if some condition isn't met (such as controlling an Earthbound Immortal without a Field Spell Card), or some condition makes the monster's existence illegal (like flipping face-up a second copy of Grandmaster of the Six Samurai), then the monster is NOT destroyed yet. The second one is that, while you did flip a monster, FLIP Effects and similar effects (like Snowman Eater) are not activated at this point either.
The third Sub-Step is the "Before Damage Calculation" Sub-Step. Some effects specificate that they activate at this Sub-Step, such as Ehren, Lightsworn Monk or Ally of Justice Thousand Arms. The other type of effect that activates here are those effects that activate when the monster is attacked while in face-down Defense Position, such as Blast Sphere. The most important aspect about this Sub-Step is that it is the last opportunity to activate ATK/DEF modifiers that aren't elligible for the next Sub-Step (as we will see in a second). Any number of chains can be started during this Sub-Step, so even if your Shrink is negated, you can activate another copy of Shrink in a new chain before moving into Damage Calculation. Once both players agree that they will not activate any more effects, we move into the next Sub-Step.
The fourth Sub-Step is Damage Calculation. This is the VIP room of the VIP room that is the Damage Step, as only a handful of effects can be applied at this point. You can certainly activate Counter Trap Cards, Quick Effects that negate activations, or some of the six exceptions, but you can no longer activate every the Spell Speed 2 ATK/DEF modifier. The only other effects that apply here will state this ability on their text or individual rulings. Some examples are Shield Warrior or Clear Vice Dragon. Only one chain can be manually started at this Sub-Step, so if the effect of your Honest is negated, you cannot activate another copy of Honest in a new chain. Hence the important of the "Before Damage Calculation Sub-Step" of unlimited chains. This single chain of effects also has a really weird rule that allows you to "assume" that previous chain links will resolve properly, for this Sub-Step only. For example, if Injection Fairy Lily attacks Blue-Eyes White Dragon, at first you will not be able to activate Kuriboh's effect, as you aren't going to take Battle Damage. However, once Injection Fairy Lily's effect is activated, you can "assume" it will resolve properly: If it did Lily's ATK would be 3400, so you would take Battle Damage, so activating Kuriboh is legal. This peculiar rule only applies here, probably due to one chain being such a small room. Once you resolve this single chain, you then apply any necessary Continuous Effects. Then, you calculate Battle Damage and inflict it. Finally, you move on into the next Sub-Step.
The "After Damage Calculation" Sub-Step is home to a lot of confusion. Let's deal first with the things we do know. Since Battle Damage was inflicted, this is the time to activate effects that activate when Battle Damage is inflicted, such as Gorz the Emissary of Darkness or X-Saber Urbellum. Also, remember those self-destructing monsters that we kept alive back at the second Sub-Step? They are destroyed at this point. FLIP Effects and similar must still wait a little longer.
The first problem we have with this Sub-Step is whether a monster is considered to be destroyed in battle at this point, or later. Many, and I do mean MANY rulings suggest that the monster(s) is/are considered to be destroyed in battle already, before starting this Sub-Step, much as how Battle Damage is inflicted at that time. The destruction is not explicitly mentioned in the chart until the next Sub-Step, which lead to believe that monsters may be destroyed later. Guess that leaves me with no choice but to adapt to each peculiar case, right Q_Q? For example, in the case of self-destructing monsters, if they were destroyed in battle, they will be considered to be destroyed in battle at this point, instead of being destroyed by their effects.
The second problem are that some Cards mention that they apply their effects during this Sub-Step, but actually activate in the next one. For example, Red Dragon Archfiend, Phoenixian Cluster Amaryllis and Gemini Soldier do activate at this Sub-Step, as their texts suggest. However, D.D. Warrior Lady and Wall of Illusion activiate in the next Sub-Step. Weird, huh? Individual rulings are very helpful for this.
There is also a weird Card called Flashbang which is activated before activating any of the other effects that you can activate at this Sub-Step. Think of it as an earlier chain. It's a weird exception exclusive to this Card.
The sixth Sub-Step is the "Resolve Effects" Sub-Step. This is the last stage for every pending effect we have piled up so far, such as FLIP Effects, the D.D. Warriors, etc. According to the chart, this is when monsters are considered to be destroyed in battle. No matter its accuracy, it's worth mentioning some properties of destroyed monsters. Their Continuous Effects are no longer applied, so Jinzo will not negate the effect of Trap Cards anymore. Destroyed monsters remain on the Field during this Sub-Step, however, they are not valid targets for targetting effects anymore.In whichever Sub-Step you consider that monsters are destroyed in battle, you would apply any "substitution effects", such as the effects of The Six Samurai, Unions, etc. After this Sub-Step is over, you should know if the battling monster(s) will be sent to the Graveyard, or if they will be redirected somewhere else (such as if Macro Cosmos is active), or if their substitutes will be sent to the Graveyard instead.
The seventh and last Sub-Step is the End of the Damage Step. Despite its name, it is still part of the Damage Step, so all the Card restrictions still apply. The first thing you perform here is to send the required monsters to the Graveyard or wherever they belong after being destroyed in battle. In this Sub-Step, you apply effects that ask for the monster to be destroyed in battle (Mystic Tomato), sent to a certain location (Sangan), or those that state that they are applied at the End of the Damage Step (Legendary Jujitsu Master).
Oh my, you actually did read through all of it T_T
It's not really complicated once you get used to it. Probably the biggest problem to keep this chart in mind is that you will never have a battle in which there is one effect activating at each Sub-Step, so it's better to memorize smaller battles and remembering their order: Enter the Damage Step, flip the monster face-up, check for any pending ATK/DEF modifiers, enter Damage Calculation, have the monsters battle, inflict damage and destroy monsters, check for any pending effects, then get rid of the monsters.
If you have any questions, feel free to drop me an e-mail at ness00[at]gmail[dot]com.