Brainstorm is one of the most powerful, if not controversial, spells available in the Legacy format at this time. There have been numerous articles written on this 'seemingly innocuous at first glance' one mana cantrip. I will be glossing over the main discussion of this card and instead focus on the specifics of using it as a part of or to initiate your doomsday piles. In many cases it can be used as any other cantrip. If you have say 2UR available post Doomsday then it is perfectly fine to build a very basic pile to win with.

One of the more difficult things of playing Doomsday storm combo is recognizing situations where you have the resources to win. Beginning players often start out with learning only a few piles by heart. While this helps with getting started, there will be many chances to win that they will miss out on.

The key thing to understand is that Brainstorm can exchange a few cards in your hand with the top of your Doomsday pile. This enables many new lines of play that will allow the Doomsday player to win in situations where the basic piles would not.

Let's discuss some examples:

You have U available. You have just cast Doomsday so storm count = 1. Your hand is BS and BW. Let's assess what we have and look at the most basic of piles to compare it with:

-> [TW/AoI], LED, LED, GP, BW            BBB+U+[1UU/2R] (7)   9 Storm

-> IU, LED, LED, GP, BW                  BBB+U+UU (6)         9 Storm

As we can see, we now have already available our finishing spell (BW). This lets us save a slot in the stack to play around with as we can use the BS to insert the BW from our hand into the pile. As a result, we have obtained the finisher, we just need to consider mana and a way to 'draw' our cards.

Examples:

BS, BW in hand.
-> LED, [TW/AoI], GP, LED, LED          BBB+U (4)             9 Storm

BS, BW in hand.
-> LED, IU, GP, LP, LED                 BBB+2U (6)            9 Storm

Example one:

  1. Cast Doomsday, build: [LED, TW/AoI, GP, LED, LED]
  2. Cast BS, draw (LED, TW/AoI, GP) and replace (TW/AoI, BW)
  3. Cast LED
  4. Cast GP, hold priority cracking LED for UUU or RRR, draw (TW/AoI)
  5. Cast TW/AoI, exile (BW, LED, LED)
  6. Cast LED (6)
  7. Cast LED (7)
    • Crack LEDs for BBB and RRR
  8. Cast BW targeting ToA
  9. Cast ToA for 9 Storm.

Thanks to BS we are able to exchange the BW in the pile with another LED. This concept of swapping can be used for many aspects of piles. In this example it means we can go off with just U open with any number of the following cards in hand:

LED, GP, [TW/AoI], BW, LM

Example two:

This follows exactly the same as example one however we require an additional 2 generic mana to pull it off.

  1. Cast Doomsday, build: [LED, IU, GP, LED, LP]
  2. Cast BS, draw (LED, TW/AoI, GP) and replace (IU, BW)
  3. Cast LED
  4. Cast GP, hold priority cracking LED for UUU or RRR, draw (IU)
  5. Cast IU, draw (BW, LED, LLP)
  6. Cast LED (6)
  7. Cast LP (7)
    • Crack LP for R
  8. Cast BW targeting ToA, hold priority and crack LED for BBB
  9. Cast ToA for 9 Storm.

Again the same concept applies however we do need one extra mana. The difference comes from the fact that we draw BW with IU, as opposed to exiling it with TW or AoI. The fact that BW is in our hand means that we can not use LED to pay for it. The Lotus Petal in the pile is used to generate R, which together with the U left floating after IU is enough to cast BW. LED is sacrificed for black in response to produce black mana, where one additional generic mana is needed to cast ToA.

Nevertheless both the above examples are cheap piles requiring relatively low resources. Assuming the opponent is at enough life and you have ToA in your maindeck you can also build the following as pile:

BS, ToA in hand.
-> LED, IU, GP, DR, LP                       BBB+U (4)   8 Storm

It follows the same lines of play as the above examples but does not require LED after the initial one used to cast IU as LP, DR and the U remaining after IU is enough to cast ToA.

Sometimes, we can get around the IU LED mana restriction simply by having extra cards in our hands. Notice that in the example above we drew IU only to put it back with Brainstorm, which is not very useful by itself. If we already had IU in hand, we could draw any card of our choice from the pile and put back IU. Since we get to put back two cards, we can put back IU and any other card in hand to effectively use Brainstrom as a draw-3 spell.

The reason this trick does not work for when we have BW in hand is that we can only put back two cards with BS, if those cards have to be IU and BW we cannot exchange any additional cards in hand with cards in the pile.

Say we have BS, IU, and one card in hand. We cast Doomsday and build:

BS, IU, X in hand.
-> LED, LED, GP, LED, BW
  1. Cast Doomsday, build: [LED, LED, GP, LED, BW]
  2. Cast BS, draw (LED, LED, GP) and replace (IU, X)
  3. Cast LED
  4. Cast LED
  5. Cast GP, hold priority and crack LEDs for UUU, RRR, draw (IU)
  6. Cast IU draw (X, LED, BW)
  7. Cast LED
  8. Cast BW targetting ToA, hold priority and crack LED for BBB
  9. Cast ToA for Storm = 9.

Obviously storm can be +1 if you are able to cast X prior to BW.

Finally let us now consider this scenario; BS and BW in hand. 1UR available. Doomsday has been cast therefore Storm Count =1.
For argument's sake let us also state that your maindeck draw spell (IU, TW, AoI) has been exiled for whatever reasons. We can still work with this scenario.

Example:

BS, BW in hand.
-> LED, GP, LED, LED, BW               BBB+1UR   (6) 9 Storm
  1. Cast Doomsday, build: [LED, GP, LED, LED, BW]
  2. Cast BS, draw (LED, GP, LED) and replace (BW, LED)
  3. Cast LED
  4. Cast GP, hold priority and crack LED for RRR, draw (BW)
  5. Cast BW targeting AoI in the SB
  6. Cast AoI, exile (LED, LED, BW)
  7. Cast LED
  8. Cast LED
    • Crack LEDs for BBB and RRR
  9. Cast BW targetting ToA
  10. Cast ToA for Storm = 10.

Again this playline can be followed with two BW in hand, BW and GP in hand or other sets of cards.

Summary

  1. You can use BS to exchange resources between your hand and the pile
  2. Don't fixate on specific lines, just remember general rules