Common Q&As: Knowledge Pool

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Thank you WOTC for creating a card destined to confuse everyone who is not a Jedi. I'm going to try and tackle a few different questions.

Q: How does Knowledge Pool work?

A: Ah, the easy one. So, if Knowledge Pool is cast and resolves, the imprint ability triggers and each player exiles the top three cards of their library into the pool. Now, let's look at what happens when a player casts a spell:

1. The player cast the spell. It is now on the stack.
2. Knowledge Pool's ability triggers and is now placed on the stack above the spell.
3. Priority is passed twice and resolution begins.
4. Knowledge Pool's ability resolves and the original spell is exiled.
5. You may now cast any spell that has been exiled by Knowledge Pool, excluding the spell you cast that triggered this ability.

A common misconception about Knowledge Pool leads to the question "what happens when Knowledge Pool is all used up?" Some people believe the only cards in the "pool" are the exiled cards from the imprint ability. However, the "pool" consists of all cards from imprinting and each card that is exiled by Knowledge Pool's second ability. Thus, the pool never runs out, since the exiled cards are constantly replaced.

Not too bad. But what about some more complicated scenarios?

Q: How do I counter a spell with Knowledge Pool out?

A: Now we're getting trickier. Let's first look at what would happen if you simply tried to counter a spell while Knowledge Pool is out.

1. Opponent casts a spell. It goes on the stack.
2. Knowledge Pool's second ability triggers and goes on the stack above it. Priority is passed.
3. You cast a counterspell. It is now on the stack above Knowledge Pool's triggered ability.
4. Knowledge Pool's second ability triggers again and goes on the stack above your counterspell. Priority is passed twice and resolution begins.
5. First, your counterspell is exiled by Knowledge Pool.
6. Now you may play any spell already exiled by Knowledge Pool, excluding the counterspell you just cast.
7a. If there is a counterspell in exile, you may cast it and target your opponent's original spell. It would resolve and the original Knowledge Pool ability would counter on resolution (fizzle).
7b. If there is no counterspell already in exile, then you may cast any spell from exile. The original Knowledge Pool ability would resolve, exiling your opponent's original spell, and he would then be able to play any spell already in exile.

Basically, unless there is a counterspell already in exile, your counterspell is only going to get exiled. The same situation occurs if you attempt to counter the spell cast from exile after Knowledge Pool's ability resolves. However, there is a clever way to get around this.

Let's look at the scenario of trying to counter the spell cast by Knowledge Pool's ability.

1. Your opponent cast a spell. It goes on the stack.
2. Knowledge Pool triggers and goes on the stack above the spell. Priority is passed twice and resolution begins.
3. Knowledge Pool's ability resolves and the original spell is exiled.
4. Your opponent then cast a spell from exile.
5. In response, you play a spell.
6. Knowledge Pool triggers and the ability goes on the stack above your spell.
7. You cast a counterspell, targeting your opponent's spell (it doesn't matter right now since it won't resolve immediately).
8. Knowledge Pool triggers again and the ability is placed above your counterspell on the stack.
9. Priority is passed twice and resolution begins (deep breath).
10. Your counterspell is exiled. You may now cast any spell exiled by Knowledge Pool except your counterspell. The spell resolves.
11. Now, your original spell is exiled. You may now cast any spell exiled by Knowledge except your original spell. You choose to cast your exiled counterspell, targeting your opponent's spell on the stack.
12. The counterspell resolves, countering your opponent's spell.

And there you have it! The same "cast a spell then cast your counterspell" trick can be used for countering your opponent's original spell, and when/if it resolves, the Knowledge Pool ability triggered by your opponent's spell would be countered upon resolution.

Q: What happens if there are multiple Knowledge Pools out?

A: Now the real fun. Let's look at two cases.

Case 1: The same player controls multiple Knowledge Pools.

This case is a bit simpler. We'll conjure up the following rule to guide us.

603.3b If multiple abilities have triggered since the last time a player received priority, each player, in APNAP order, puts triggered abilities he or she controls on the stack in any order he or she chooses.

Let's say you control two Knowledge Pools and you cast a spell. You get to choose the order in which the triggered abilities goes on the stack, and thus, which resolves first. Basically, you get to choose which Knowledge Pool to pull your spell from. Let's check it out.

1. You cast a spell.
2. Knowledge Pool A and Knowledge Pool B trigger.
3. You choose to place Knowledge Pool B's ability on the stack first, then Knowledge Pool A's ability.
4. Priority is passed twice, and resolution begins.
5. Your original spell is exiled by Knowledge Pool A. You may now cast any spell exiled by Knowledge Pool A, except your original spell.
6. You cast the exiled spell, and it resolves.
7. As Knowledge Pool B attempts to resolve, it is countered since the original spell can not be exiled, as it already has been exiled.

Case 2: Multiple players control Knowledge Pools.

For the sake of simplicity, let's keep this to a two player game to start. We'll run through a scenario, then come to a conclusion from it.

1. You cast a spell.
2. Your Knowledge Pool and your opponent's Knowledge pool both trigger.
3. Following APNAP order, your Knowledge Pool's triggered ability goes on the stack first, then your opponent's Knowledge Pool's triggered ability goes on the stack.
4. Priority is passed twice, and resolution begins.
5. Your original spell is exiled by your opponent's Knowledge Pool, and you can cast any spell that has been exiled by your opponent's Knowledge Pool, except your original spell.
6. You cast the exiled spell, and it resolves.
7. As your Knowledge Pool's ability attempts to resolve, it is countered since your original has already been exiled.

To generalize, the active player will always be casting out of their opponent's Knowledge Pool. If we expand this to a multiplayer game, the active player will always be casting out of the farthest opponent to the left's Knowledge Pool (if everyone in a multiplayer game had a Knowledge Pool out, the active player would be casting out of the opponent to their right's Knowledge Pool).

Summation: Knowledge Pool is the most complicated card I have encountered in my short time playing Magic, but it is not impossible to understand. I can't wait to see some games played with it.