Saturday, July 4, 2015

A non-existent mana cost

There's a principle (well, rule really) in Magic that goes like this: A non-existent mana cost cannot be paid.

What does this mean?

Consider this scenario: You have a Living End in your graveyard, and you cast a Snapcaster Mage, and use it to give the Living End flashback. Can you then proceed to cast Living End from your graveyard?


The answer is no, you can't. And the reason for this is the principle: A non-existent mana cost cannot be paid.

Living End has no mana cost. This is not the same thing as having a mana cost of 0. (If its mana cost were 0, then it would have a mana cost symbol with 0 on its upper right corner.) It has no mana cost at all. This means that it can't be cast in the normal way (because paying its mana cost is part of the casting process, and in this case that step cannot be done, because it has no mana cost.)

(Note that Living End has a converted mana cost of 0. However, this is a completely different and unrelated thing. That value is used only for effects that look for converted mana cost explicitly. Casting does not look at converted mana costs.)

Snapcaster Mage adds flashback to the card when it's in your graveyard, and it states that the flashback cost is its mana cost. However, as stated, the card has no mana cost! This means that it has no flashback cost either, and a non-existent cost can't be paid. Therefore you can't cast it using Snapcaster Mage either.

So how exactly is Living End cast, then? Using its suspend ability. Suspend works like this: If the card is in your hand, any time you could cast the card (ie. obeying timing restrictions for the card type) you may pay the suspend cost, which moves the card into exile with the specified number of time counters. At the beginning of your upkeep you remove one time counter from it, and when the last time counter is removed, you may cast the card without paying its mana cost.

That last part is the crucial difference: The effect allows you to cast the card "without paying its mana cost". Any effect that uses that wording bypasses completely the mana cost of the card, and thus we don't even look at what it is (or, like in this case, whether it even exists.) The effect instructing you to cast the card doesn't require paying any mana cost, and thus the card can be cast.

Consider Living End with these two cards:


Act on Impulse exiles the top three cards of your library, and allows you to cast them (from exile) until end of turn. Even though the cards are in exile rather than in your hand, the casting process is identical. Therefore you can't cast Living End this way, because you can't pay its mana cost. (Incidentally, you can't suspend it either, because the suspend ability can only be used if the card is in your hand.)

Chandra's third ability exiles the top ten cards of your library. You then choose an instant or sorcery card among them, copy it three times, and then you may cast these copies without paying their mana costs. This, thus, does allow you to cast (the copies of) Living End, as mana cost is irrelevant.

As an unrelated side note, notice that these two effects behave different with regards to timing restrictions.

With Act on Impulse you have to obey the timing restrictions of the card (in other words, if the card is a sorcery or a creature without flash, you can only cast it whenever you could normally cast a sorcery, ie. in your main phase when the stack is empty.) With Chandra's third ability, however, you cast even sorceries immediately, ignoring their timing restriction (ie. even if the stack is not empty, and even if this somehow wasn't your main phase.)

The reason for the difference is that in the former case the effect allows you to cast the cards during a time period (ie. "you may cast these cards until (some time in the future)"), while in the latter case the effect instructs you to cast the cards immediately, while the effect is resolving. Whenever an effect instructs you to cast a card immediately, you do so disregarding the card's type; whenever an effect allows you to cast a card during a period of time (ie. until end of turn or whatever), you have to obey the timing restrictions of the card type.

Saturday, June 6, 2015

The problem with shuffling in MtG

Most competitive card games, where each player has a deck of cards that needs to be randomized, have one very major problem: Experienced cheaters can masterfully manipulate and "stack" the deck while shuffling, without their opponent or anybody else noticing. (This kind of cheating is sometimes caught on camera. With camera footage we have the advantage of seeing the shuffling as many times and as closely as we want, and in slow motion. In a real-life situation it's much harder, especially if we don't know what to look for, and sometimes even then.)

Experienced cheaters can stack the deck by moving certain cards to the top or the bottom of the deck.

To minimize the possibility of cheating, MtG tournament rules require for the opponent to also shuffle the deck afterward. The problem with this is that even though you can't stack your own deck, you can do it for your opponent's deck. For example you can mana-flood or mana-screw your opponent by stacking their deck appropriately.

Poker doesn't really have this problem because if you shuffle the deck, you have to present it to an opponent, and said opponent must only cut the deck once. (In fact, cutting it more than once, or even outright shuffling it, is forbidden at most places. It must be cut, and cut only once.) This way neither player can manipulate the deck. The shuffler can't know where the opponent will cut the deck, so there's no way to make certain cards end up on the top. (The only exception to this is that if both players are working together, and the other player cuts the deck where the shuffler "marked" it. This is a common cheating tactic in poker, but it only works if two players are working together, and only if they are sitting side by side on the table, as the cut is always made by the next player.)

Many have suggested using this same principle in MtG. In other words, shuffle your deck, and then your opponent cuts it once, and that's it. However, unlike in poker, this isn't a very effective anti-cheat measure in Magic. Yes, it prevents you from getting the cards you want on the top (or bottom, in the case of your opponent's deck in some situations), but there's another cheat that a single cut doesn't prevent: Mana weaving.

Mana weaving is distributing the lands evenly in the deck, so that you get a steady supply of lands and do not get mana flooded or mana screwed. An expert cheater can more or less easily mana weave their deck (eg. by shuffling in such a way that most lands go eg. to the bottom of the deck, and then mash-shuffling that bottom part into the rest of the deck once.) This is blatant cheating, of course, because the deck is not randomized.

And the thing is, a single cut to such a deck isn't going to undo any such mana weaving. And that's why the poker way doesn't really work in Magic. The opponent really needs to shuffle the deck in order to undo any possible mana weaving, and make the deck truly randomized. But, of course, when you can fully shuffle a deck, it allows cheating.

This is a dilemma that has no practical solution.

At the highest levels of poker cheating by shuffling trickery is impossible because players do not shuffle nor are allowed to touch the deck in any way. It's shuffled by a neutral dealer, employed by the tournament organizer or the casino.

In MtG tournaments the same could work if judges always shuffled the players' decks. The problem is that a typical tournament has over a hundred players and only a few judges. This solution is just impossible to implement in practice. (This could work on the top-8 matches, but for some reason it's not done that way. Perhaps it's not really needed either. The top-8 matches are always videoed and very closely watched, and it can be fairly assumed that nobody dares to cheat there. Although it does happen from time to time...)

Tuesday, May 26, 2015

Is color a copyable value?

Simple question: Is the color of a permanent a copyable value? (In other words, if something copies that permanent, will it also copy its color?)

The intuitive answer would be "of course it is!" Naturally it's not that simple.

Copyable values are listed in rule 706.2. They are: "name, mana cost, color indicator, card type, subtype, supertype, rules text, power, toughness, and/or loyalty".

Note that "color" is not among them. "Color indicator" is, but that's not the same thing. To understand the difference, assume that the color of a permanent were changed by something like Thoughtlace (which says "Target spell or permanent becomes blue.") That spell won't add a color indicator to the permanent; it will simply be a continuous effect that changes its color. If that permanent were to now be copied, it won't have that changed color, but the original one of that permanent.

The color of a permanent is derived from its other info. This is actually explicitly explained in the next rule, ie. 706.2a, which says: "A copy acquires the color of the object it’s copying because that value is derived from its mana cost or color indicator."

In other words, to derive the (copyable) color of a permanent, we look for one of these:
  1. If it has a colored mana cost.
  2. If it has a color indicator. (If it does, it overrides the color derived from the mana cost.)
  3. If it has an ability of the form "(this) is (color)". (Very rare nowadays.)
So the next question is: If something creates a token that is, for example, a "1/1 green Snake creature", it will have no mana cost, no color indicator, and no abilities. If now something copies this permanent, will it be green?

From all the information given above, the answer would seem to be "no". After all, the copy has no mana cost, no color indicator and no abilities either, and as rule 706.2a said, those are the ones that would determine its color.

However, the real answer is "yes", but the reason for it is quite unclear and indirect (and, in my opinion, one of the shortcomings of the current rules, as they do not state this very clearly).

The list above was actually incomplete. There is a fourth case, but this additional case is very indirectly implied in a completely different rule pertaining to tokens. This fourth case would be:
  1. If it's a token, and the effect that created it specified its color.
A special rule governs this situation. In this case "color" does become a copyable value of the permanent, and it will become copied if something copies it. This fact, however, is currently very unclear, and can only be inferred indirectly. The actual rule where this is inferred from is the following:
110.5b The spell or ability that creates a token may define the values of any number of characteristics for the token. This becomes the token’s “text.” The characteristic values defined this way are functionally equivalent to the characteristic values that are printed on a card; for example, they define the token’s copiable values. A token doesn’t have any characteristics not defined by the spell or ability that created it.
If you are confused, don't worry. So am I. But yes, that rule effectively means that "color" is a copyable value of the token (even though it's usually not for any other permanent).

Sunday, February 15, 2015

Can zones be targeted?

There are several things in Magic the Gathering that can be targeted by spells and abilities: Cards, permanents, players, spells (including copies of spells)...

Question: Can zones be targeted?

At first this question might seem silly. After all, what sense would something like "target battlefield" make? (After all, there is only one battlefield, and it would make little sense to "target" it with anything.) However, perhaps a bit surprisingly, the rules of the game support the possibility of targeting a zone. The exact rule that defines targeting is (emphasis mine):

114.1. Some spells and abilities require their controller to choose one or more targets for them. The targets are object(s), player(s), and/or zone(s) the spell or ability will affect. These targets are declared as part of the process of putting the spell or ability on the stack. The targets can’t be changed except by another spell or ability that explicitly says it can do so.
There are some zones that are more sensible to be targeted because they exist per player. Namely graveyards, libraries and hands. Of course normally these are always referred to by targeting the player, not the zone (ie. "target player's graveyard", "target player's library", and "target player's hand".)

To my knowledge, however, there exists one card that targets a zone directly: Circu, Dimir Lobotomist.


It says: "Whenever you cast a blue spell, exile the top card of target library." (Also the second ability targets a library directly.)

The funny thing about this card is that there's no reason why it couldn't say "target player's library", other than that the text wouldn't fit if it said so. Even more curiously, as far as I'm aware, the possibility of targeting a zone was added to rule 114.1 precisely for this one card.

Monday, January 26, 2015

Attacking costs

Question: You control a Floodtide Serpent enchanted with Ordeal of Heliod. You attack with the serpent and return the ordeal to your hand. Does the triggered ability of ordeal trigger?


Most players' intuition would be that it doesn't trigger. In this case the intuition is correct (rare for this blog.) The interesting question is, however, why exactly.

Declaring attackers is a bit more complex of an operation than most players are aware of. It actually resembles the process of casting spells and activating abilities.

Casting a spell technically follows the following procedure (highly condensed here): Announce the spell you are going to cast by revealing it (it moves to the stack), make any possible choices for the spell (possible modes, value of X, alternative or additional costs to be paid, color choice of hybrid mana symbols), choose targets (if it has any), determine the total cost of the spell, activate mana abilities, and finally pay the costs. After all this has been successfully and legally done, the spell is considered successfully cast (and anything that triggers on such a spell being cast triggers now.)

(If at any point it turns out that one of those actions is illegal, everything above is reversed, and none of it is considered having happened.)

Activating abilities is almost identical to the above (with the only difference being that it's not a spell that's put on the stack, but an ability.)

Perhaps a bit surprisingly, but very consistently, declaring attackers (and also declaring blockers) follows a procedure that's very similar. First you announce which creatures are going to attack, then you choose what they are attacking (ie. which opponents or planeswalkers those opponents control), then you determine the possible costs required for this to happen, then you can activate mana abilities, and finally pay the costs (if there are any). After all this has been successfully and legally done, the creatures are considered successfully declared as attackers, and anything that triggers on such a creature attacking triggers now.

(If at any point it turns out that one of those actions is illegal, everything above is reversed, and none of it is considered having happened. This includes in this case checking that no restrictions are broken, and that the amount of requirements that can be fulfilled with a legal declaration has been maximized.)

Note how costs are paid before a creature is considered having attacked, and returning an enchantment to its owner's hand is a cost for Floodtide Serpent to attack. Thus the ordeal returns to your hand before the serpent has attacked, and thus it doesn't trigger.