ATK/DEF modifiers are usually left behind for more powerful effects like destruction or Removing Cards from Play, but lately, modifiers with a few modern additions have been created. For example, Gale the Whirlwind not only provides an ATK/DEF halving, but it is also a Tuner monster that can be easily Special Summoned, and there's also new age Equip Cards that recycle themselves to compensate the loss of losing their target. No matter the reason why you use ATK/DEF modifiers, there's a certain complexity behind how they work.
Before we start, this article will be about general guidelines about ATK/DEF modifiers. There are some really, really awful official rulings about modifiers that should have been reversed a long time ago. For example, half of Shrink's rulings. Explaining some guidelines here won't change what is written, but at least it will help fixing some inconsistencies that may float around. As a final note, it should be obvious that whatever applies to "ATK" also applies to "DEF", so I won't be using both terms all the timing. It sure is exhausting to type 3 characters.
The first concept that one needs to understand is the difference between Original and Current ATK. A long time ago, the Original ATK of a Card could only be the value written on the Card itself, but later, some Original ATK modifiers appeared. Still, the Original ATK of a Card is either the value printed there, or the value set by some rare effects like Unstable Evolution. The Original ATK of a "?" ATK monster is zero while face-up on the Field by default, but some effects may modify this. The current ATK of a monster is the ATK value defined by every modifier. For example, Blue-Eyes White Dragon has 3000 Original ATK, and equipping Axe of Despair would make it have a Current ATK of 4000, while its Original ATK is still 3000 (because Axe doesn't modify the Original ATK). Now, Tragoedia has an Original ATK of "?", that is to say, zero. Its effect causes a modification on its Current ATK, so that it has 600, 1200, 1800, etc. as its Current ATK, but its Original ATK is still zero. Equipping Axe of Despair only increases these multiples of 600, but zero remains as the Original ATK. Only equipping something like Unstable Evolution can change this value.
Once we separate Original ATK from Current ATK, there's another division to keep in mind. Modifiers work in two ways: Either, they add or substract some ATK/DEF, or they set a completely new value. The first type of modifier is pretty simple. Much like we saw at the Kalut vs. Kalut example in a previous article, you simply add (or substract) all modifiers until you reach a new value. For example, if you equip a copy of Axe of Despair, you add 1000 ATK to the current ATK. If you equip two copies, you add 2000, etc.. If Burden of the Mighty is played, then you substract some of the ATK you added, and so on. This first type of modifier is identified by terms like "gains 100 ATK", "loses 500 ATK", "increase the ATK by 500", "reduce the ATK by 1000".
The type of modifier that becomes problematic are those that set a value. Basically, you ignore the current ATK and say "now your ATK is this". If two modifiers that set a value try to be applied to the same monster, then the last one to resolve takes precedence. For example, if Blue-Eyes White Dragon is affected by Black Garden (halving its ATK to 1500 permanently), and is later affected by Shrink (halving its Original ATK value to 1500, without affecting the Original ATK, until the End Phase ), then Blue-Eyes will have its ATK restored to 3000 at the End Phase, since Shrink takes over Black Garden's effect. The ATK is the same, but the duration isn't.
The main problem comes from the interaction between the modifiers that add ATK, and those that set a value. That's why we need even more divisions Q_Q The modifiers that add or substract ATK can be divided between those that are continuously applied, like Botanical Lion or Black Pendant. An important note that is there are Monster Effects that are not Continuous, but still count as continuously applied. These are monster effects that can ONLY affect the monster that generates it. For example, Card Trooper has an Ignition Effect to increase its own ATK only, so it counts as continuously applied. However, Sirocco the Dawn has an Ignition Effect that increases the ATK of any Blackwing monster, so even if it targets itself, it will not count as continuously applied.
The other division we need is among modifiers that set a value. These are divided between those that "freeze" the current ATK value and modify it, and those that don't. The ones that "freeze" a value are pretty rare, but they are also the newer ones, which means that they are more powerful and popular. Just keep the names in mind, and I'll explain their interaction in a second. Now that we know what I hopefully think it's all we need, let's look at the examples:
#1) Temporary addition/substraction vs. non-freezing value, affecting Current ATK: Do NOT re-apply the temporary modifier. For example, if you target Plague Wolf (1000) with Rush Recklessly (1700), and activate Wolf's effect (2000), do not re-apply Rush Recklessly's effect at any point. This may be clearer with another example: If you target Clear Vice Dragon (0) with Rush Recklessly (700), and apply Clear Vice Dragon's effect attacking Jinzo (2400 * 2 = 4800, ignoring the 700 ATK bonus), you never re-apply Rush Recklessly. Not after the new Current ATK is determined, and not after Damage Calculation is over. If the other is reversed (set a value -> use temporary addition), then there are no problems. For example, if you use Wolf's effect (2000) you can target it with Rush Recklessly and simply add 700 ATK (2700).
#2) Temporary addition/substraction vs. freezing value, affecting Current ATK: Same as above, only that the interaction is harder to see. For example, if Jinzo (2400) is targeted by Rush Recklessly (3100), and then, Limiter Removal is activated (6200), Rush is no longer applied. It's not as evident as the Plague Wolf example, because it seems that Removal is taking into account the 700 ATK bonus. This will be clearer in example #4.
#3) Continuously applied addition/substraction vs. non-freezing value, affecting Current ATK: Re-apply the continuous modifier. For example, if you equip Plague Wolf (1000) with Axe of Despair (2000) and activate Wolf's effect (2000), you DO re-apply Axe of Despair now, and add 1000 ATK (3000). Of course, if the Card that sustains the addition or substraction is no longer there, you no longer apply it, so if Axe is destroyed, Wolf's ATK goes back to being 2000.
#4) Continuously applied addition/substraction vs. freezing value, affecting Current ATK: Do NOT re-apply the temporary modifier. Once again, this isn't as obvious as example #3, as the freezing value takes into account the previous modifier. For example, if you equip Jinzo (2400) with Axe of Despair (3400) and activate Limiter Removal (6800), the Axe bonus is actually no longer applied. How can one tell? Because of a very simple fact: If you destroy Axe of Despair, Jinzo's ATK will remain at 6800. This is much clearer than using Rush Recklessly, because Axe can be destroyed, negated, and other forms of stopping its effect. For example, using Imperial Order and getting rid of it (turning Axe off and on) will still keep the ATK at 6800.
#5) Modifier vs. changing the Original ATK: This heavily depends on which values each modifier refers to. For example, Shrink has to look at a new Original ATK, and then you re-apply it. However, Limiter Removal only cared about the Current ATK value that the monster had at the time it was doubled, so you do not need to recalculate anything. In short, only recalculate if the modifiers need to check the new Original ATK value, and if they can be re-applied, following the examples above. For example, if I activate Rush Recklessly and target Plague Wolf, then activate Wolf's effect (which ignores Rush and sets the ATK at 2000), and later activate Unstable Evolution, I won't need to re-apply Rush Recklessly because of example #1. However, since Wolf's effect does involve Original ATK, and it has been modified, I will have to double the value set by Unstable Evolution (1000 -> 2000, or 2400 -> 4800).
I think that covers every possible interaction. All it takes now is some reading on each peculiar Card to figure out which type does it belong to. With all of this info, it is much easier to explain what's wrong with Shrink, but I'll leave that for the next article, so that you can digest this without anti-acids. If you have any questions, feel free to drop me an e-mail at ness00[at]gmail[dot]com.