Building the Perfect Affinity Sideboard

Last week, I discussed the main deck card options for Modern Affinity. Today, as promised, I will continue with sideboard card options, matchups, and rough sideboard plans.

For reference, here is the list I played at Pro Tour Oath of the Gatewatch:


I explained last week that (if you don’t want to move to a different version with Tezzeret, Agent of Bolas and Ensnaring Bridge to deal with the Eldrazi menace) I would replace the main deck Ensoul Artifact with a Galvanic Blast, but apart from that, I liked the main deck.

What’s up with all the 1-ofs?

There are a lot of 1-ofs in my main deck and even more in my sideboard. This may seem weird, but I have several strategic reasons for this choice. The gist is that I like seeing one in my hand but often not two. But let me break it down in a bit more detail.

First, there are diminishing returns. I’ll explain with an example. Suppose that, for the sake of the argument, you have two free sideboard slots and you can either go with 2 Rule of Law, 2 Torpor Orb, or 1 Rule of Law and 1 Torpor Orb. Moreover, for this example, suppose that Rule of Law only comes in against Storm (7% of the metagame) and Torpor Orb only comes in against Abzan Company (8% of the metagame). These numbers are not meant to reflect the actual metagame but are here to provide a concrete example. If you have a hate card in the top 10 cards of your library, you gain a certain bonus B to win in those matchups, but—and this is where diminishing returns come in—a second one brings no further bonus. The probability of drawing at least one hate card in your top 10 is 16.7% when it’s a 1-of and 30.8% when it’s a 2-of. So the expected bonus in an arbitrary matchup is as follows:

  • 2 Torpor Orb: 8% * 30.8% * B = 0.0246B
  • 2 Rule of Law: 7% * 30.8% * B = 0.0216B
  • 1 Torpor Orb, 1 Rule of Law: 8% * 16.7 * B + 7% * 16.7 * B = 0.0250B

For this reason, conceptually at least, I like to go for the two 1-ofs. Of course, if one card or deck is much better than the other, then this may change, but I wanted to illustrate the general thought process.

Secondly, especially for a deck like Affinity, every sideboard card you add requires you to cut an engine card, which cuts into the deck’s power and explosiveness. In the previous example, I focused on added benefits of sideboard cards, but I didn’t incorporate the reduction in artifact synergies. This is an increasing, convex function of the number of cards you remove. In other words, removing 1 Memnite or Signal Pest is not a big deal, but the more of these cards you cut, the worse Mox Opal and Springleaf Drum get. Oversideboarding is dangerous, and it’s another reason why I’d rather board in 1 card in two matchups than 2 cards in one matchup. Having more 1-ofs allows me to do so.

Thirdly, 1-ofs are fun and keep the opponent off-balance. I enjoy the variety in game play that results from many one-ofs, and it’s nice that opponents never know how many copies of a card I have. Sometimes they assume I will play more and make plays or sideboard decisions in subsequent games accordingly, which turn out to be poor when I’m only running a single copy of that card.

Now, let’s just go over all the sideboard card options one by one. I’ll indicate when I consider a certain card to be a “must” and when I view it as optional.

Artifact Hate

Where else to start than with cards for the mirror match? Vandalblast and Hurkyl’s Recall had been worse than Ancient Grudge in my testing, but I reconsidered Vandalblast after the introduction of Ghirapur Aether Grid. Although it potentially allows you to beat an active Aether Grid, the overload cost is still hefty. In too many games, you’ll still be forced to play it for the normal cost before a Steel Overseer or Master of Etherium overruns you, and if you have to play it for the normal cost, I’d rather have an Ancient Grudge in my graveyard. Besides that, you can reasonably board in 1-2 Ancient Grudge versus Colorless Eldrazi or Tron, whereas the alternative artifact hate cards are not efficient for those matchups.

In my sideboard, I want 2 Ancient Grudge for sure. More is optional, especially since it can have the downside that you either have more than 8 colored spells in your deck (which can too frequently lead to awkward hands with multiple colored spells and no colored source) or have to start boarding out Master of Etherium to balance it out (which doesn’t yield a huge card quality increase). If you also have 2 Ghirapur Aether Grid for the mirror match, I recommend a limit of 2 Ancient Grudge.

Enchantment Removal

Some of these destroy artifacts as well. Although Ghirapur Aether Grid has increased the value of Wear // Tear in the mirror match, I still prefer Ancient Grudge because it’s a 2-for-1 guaranteed. Wear // Tear needs them to have Grid and you to have 2-colored mana for it to yield a 2-for-1.

If you want a slot to deal with fast enchantment-based combos like Retreat to Coralhelm or Jeskai Ascendancy, or enchantment-based Prison decks (all of which might actually be reasonable against the Eldrazi decks) then Wear // Tear is a fine option that you can also add in the mirror match. You can go for Nature’s Claim instead if you expect a lot of Burn decks (because you can destroy your own artifact, especially one that is already targeted by Destructive Revelry, to gain life), but there doesn’t seem to be a lot of Burn around these days.

Ray of Revelation or Back to Nature are the more dedicated slots if you expect a lot of these enchantment-based decks or Bogles, but the metagame is not at that point now. By the way, I’ve seen Worship appear in more and more sideboards to fight Eldrazi. If people board in Worship (as their only enchantment) against you as well, then I wouldn’t bother with Ray of Revelation. Instead, just win through Inkmoth Nexus.

Finally, don’t board in Wear // Tear against Stony Silence. Wear // Tear is hard to cast because Mox Opal and Springleaf Drum are shut down, and you can’t keep a mana open all game long in anticipation. Moreover, you can’t afford to be stuck with Wear // Tear in your hand when your opponent doesn’t have Stony Silence.

At the moment, I don’t recommend any anti-enchantment cards in the sideboard.

Ghirapur Aether Grid

Ghirapur Aether Grid is a sweet, relatively new addition that is great in the mirror match and against Infect. I also tend to bring in one against super-slow Grixis control decks and against Abzan decks with Lingering Souls and Stony Silence, but not two because I’m already straining the 3-drop slot with Etched Champion in those matchups and drawing multiple Grids is really bad.

In my sideboard, I want 1 Ghirapur Aether Grid for sure. The second one is optional. I had two at first during testing, and then I went back to 1 when I noticed that it can be too slow against the new Affinity versions with 4 Master of Etherium to boost creatures’ toughness.

Cards Against Creature and Removal-Heavy Decks

I already covered these cards in my article last week as they’re quite good against Jund or Zoo, and they should be up for main deck consideration in the right metagame. In the sideboard, I prefer Etched Champion, but Hangarback Walker is an option if everyone is playing multiple Shatterstorms or Creeping Corrosions.

I want 1 Etched Champion for sure in the board, preferably at least 2. More is optional and depends on metagame expectations. I had 3 at the Pro Tour, but given the nearly mono-colorless metagame we live in right now, I don’t mind cutting it back down to 2.

Generic Countermagic and Discard

Spell Pierce is a nice piece of interaction against combo decks. It is effective against Burn as well. Stubborn Denial fills a similar role, but it is better against Scapeshift or Tron decks. Unified Will is expensive, but it’s better than the alternatives if your 75 includes multiple Chalice of the Void that you plan to play for X=1.

Stubborn Denial and Spell Pierce are on a similar power level, but I have a small preference for Stubborn Denial, especially with 4 Master of Etherium to turn on ferocious. One peculiar interaction is against Simian Spirit Guide. If your opponent Dismembers a 3/3 Arcbound Ravager while tapped out and you cast Stubborn Denial without ferocious, then your opponent can let the Denial resolve and exile Simian Spirit Guide as Stubborn Denial is resolving—you cannot respond to them paying 1 by sacrificing another artifact to turn on ferocious at that point. So make sure your Ravager is a 4/4 before passing priority on the Denial if you suspect your opponent has a Simian Spirit Guide!

The discard spells have the dual purpose of disrupting combo decks and fighting hate cards like Stony Silence. I prefer Thoughtseize over Duress because it has more applications. In particular, you can bring it in against a creature-based deck in the hope of snagging their Stony Silence and you still have the option to discard a creature if they don’t hold the enchantment. On the other hand, Duress is playable against Burn.

In my sideboard, I want 1 Thoughtseize and 1 Stubborn Denial for sure. Additional discard/countermagic slots are optional. It’s nice to have two cards that can come in against a variety of matchups, but you don’t want too many of them because they come at the opportunity cost of more powerful targeted hate cards.

Spot Removal

Against decks that rely on creature-based “combos,” such as Affinity, Infect, and Abzan Company, it helps to have some spot removal next to the Galvanic Blasts in the main deck. Against Eldrazi, answering a quick Thought-Knot Seer can also prove useful.

Dispatch may look nice (and it can deal with a 6/6 Endless One or exile Kitchen Finks) but it has the problem of being a colored card. Slaughter Pact has the same problem. In a deck with only 12 colored sources, I don’t want to overload on colored spells.

Gut Shot and Dismember can be cast with Phyrexian mana if you do not draw a colored source, and for that reason, I prefer them over Dispatch. Gut Shot can be an amazing 0-mana swing against Steel Overseer, Inkmoth Nexus, Kataki, Glistener Elf, and so on, but Dismember is better against Master of Etherium, Thought-Knot Seer, Spellskite, or an opponent who plans to save their creature with a Blinkmoth Nexus or Pendelhaven pump. Overall, I prefer Dismember because it kills a larger set of creatures.

Dismember could even be a main-deck inclusion. I forget to mention it last week because I have always preferred Galvanic Blast in that slot for the reason that it is not dead against decks like Tron or Scapeshift. I still prefer the more flexible Galvanic Blast in my main deck, but I admit that the current Modern metagame is more creature-heavy than it has been in a long, long time. So I don’t oppose a main-deck Dismember.

In my sideboard, assuming that I don’t already have multiple Dismembers in my main deck, I want 1 Dismember for sure. An additional copy or a Gut Shot is optional.


Good against decks with Lingering Souls and multiple other cheap low-toughness creatures, decks with Eldrazi Skyspawner and Eldrazi Mimic, decks with Noble Hierarch and either Melira or Glistener Elf, random decks like Elves, and many more.

In the current Modern metagame, there are plenty of decks with small creatures, so I want 1 Whipflare for sure in my sideboard. More is optional, especially if you already have the second Ghirapur Aether Grid.


If there is a lot of Infect around and you want a good card that will not be destroyed by their Viridian Corrupter or Nature’s Claim, then this is a reasonable option. Currently, there is not enough Infect in Modern to make it worthwhile, but I mention it because it illustrates a general point: non-artifact cards are sometimes better sideboard cards because they aren’t affected by the hate cards that opponents are already boarding in against you.

Anti-Combo Cards

Decks like Storm, Ad Nauseam, and Living End have a hard time winning when they can’t cast multiple spells per turn. So Rule of Law or Eidolon of Rhetoric are reasonable options if those decks are popular. Eidolon of Rhetoric can attack and pick up a Plating, but I prefer Rule of Law because it’s not affected by Dismember or Slaughter Pact.

Stain the Mind is also good against the combo decks mentioned above but has more applications because it can snag Griselbrand, Scapeshift, and so on. What’s more, you can convoke it via Vault Skirge.

Currently, all of these combo decks are not super popular, so I see all of these anti-combo cards as optional.

Generic Hate Cards That Are Also Artifacts

What all of these cards have in common is that they are artifacts, which is sweet because they help turn on Mox Opal and boost Cranial Plating.

Chalice of the Void is a good interactive card against combo decks like Infect (for X=1) and Living End (for X=0). I would also board it in against Burn and Tron, but only when I’m on the play.

Spellskite is great against Bogles and Infect, and decent against Jund, Affinity, and Eldrazi. It has the widest applicability of the artifact cards in this group. A problem is that many Infect decks have good answers to it post-board, including Twisted Image, so you can’t expect it to live.

Torpor Orb is good against Abzan Company and random other decks that rely on enters-the-battlefield triggers. You can even board it in against blue Eldrazi versions with Eldrazi Mimic, Eldrazi Skyspawner, and Drowner of Hope.

Ultimately, I view all of these cards as optional. I had a Chalice and a Spellskite at the Pro Tour, but if I want to find room for more dedicated anti-Eldrazi cards, then I wouldn’t mind cutting them.

Anti-Eldrazi Cards

I talked about these cards last week. Painter’s Servant is fragile, but it’s good at shutting down Eldrazi Temple, Eye of Ugin, Eldrazi Mimic, and more.

Ensnaring Bridge is a fine option too, but you have to pair it with alternative win conditions like Tezzeret, Agent of Bolas. Ghirapur Aether Grid is an option for that role as well, and it isn’t terrible against Eldrazi lists with Eldrazi Skyspawner and Stony Silence, but it’s still fairly low-impact if you draw it without Ensnaring Bridge.

I don’t like Worship all that much because it’s a 4-mana colored card, and when the opponent eventually draws World Breaker, I’d rather be at 15 life with an Ensnaring Bridge and a reasonable board presence than at 1 life with a Worship in play.

In my sideboard for the current Modern metagame, I want 2 anti-Eldrazi cards for sure. More than 2 is optional. Due to my fondness for 1-ofs, I like a mix between Painter’s Servant and Ensnaring Bridge the best, but this is based on theorizing, not testing.

Blood Moon

Blood Moon is another card that can attack the mana base of the Eldrazi decks. A turn-3 Blood Moon on the draw will often be too slow because they will have emptied most of their hand by then, but a turn-2 Blood Moon on the draw, or a turn-3 Blood Moon on the play should be good. Shutting down utility lands such as Ghost Quarter is relevant, too, but that’s a double-edged sword.

A problem is that Blood Moon shuts down your own Nexuses. This, by the way, is a key reason why I haven’t been boarding in Blood Moon against Tron. In that matchup, your creaturelands are quite important, and losing them helps your opponent considerably. Besides that, Tron players can easily destroy Blood Moon with Oblivion Stone. Against Eldrazi decks, Blood Moon is mediocre for a similar reason. Nevertheless, it can be powerful against Abzan decks and it can put a halt to Scapeshift.

Although Scapeshift hasn’t been putting up good numbers lately, it is a one-card combo deck that is not affected by creature removal, so I expect that a properly built version has the potential to defeat the Eldrazi menace. Since Modern currently seems to be dominated by creatures and because countermagic is embarrassing against Cavern of Souls on Eldrazi, I would go for a black/green Scapeshift deck instead of the usual blue/green variant. You can replace Serum Visions with Beseech the Queen, and you gain the blowout potential of a turn-3 Damnation. Add Shriekmaw and Thoughtseize to deal with Reality Smasher, and you should have enough time (in theory at least) to find cast a lethal Scapeshift.

BG Scapeshift

This is just a quick, untuned build to help us answer the question of “Do we need Blood Moon in our Affinity sideboard?” so I don’t have a sideboard yet. Night of Soul’s Betrayal will be in there for sure, but apart from that, I would have to spend hours to scour for Beseech the Queen targets.

I think this Scapeshift deck has potential but I would still be surprised if it starts dominating, and Blood Moon is decent if unspectacular against Eldrazi decks. All in all, Blood Moon is an option but I don’t view it as a mandatory inclusion.

Graveyard Hate

All of these cards are excellent against Goryo’s Vengeance. Rest in Peace is arguably the most powerful, but it requires colored mana and stops your Arcbound Ravager’s modular triggers, so I like the other cards more.

All except for Grafdigger’s Cage are good against Living End. On the other hand, Grafdigger’s Cage is excellent against decks with Collected Company, Chord of Calling, and Kitchen Finks combos. Since that deck seems well-positioned to take on the Eldrazi menace, I want to be prepared for it at my next Modern tournament.

Therefore, I want 1 Grafdigger’s Cage in my sideboard for sure. More graveyard hate is optional.

New Options from Oath of the Gatewatch

Warping Wail is like a Galvanic Blast/Spell Pierce split card that is worse and more expensive, but flexible and colorless. I considered it for the Pro Tour, but because cutting cards is always so hard while sideboarding, I preferred more powerful cards over more flexible cards in my Affinity list. Therefore, I didn’t include Warping Wail.

Sea Gate Wreckage is nice for the grindy matchups as it helps you fight back against cards like Ancient Grudge. It also allows you to go up to 18 lands against Abzan, where I want to increase my curve by bringing in Etched Champions and retaining Master of Etherium. At the Pro Tour, I had 1 Sea Gate Wreckage in my sideboard. It was okay, but I’m not sure the current metagame is grindy enough to make repeatable card drawing worthwhile, so I don’t see it as a mandatory inclusion.

General Sideboard Advice

To summarize, I view the following slots as must-haves:

2 Ancient Grudge
1 Ghirapur Aether Grid
1 Etched Champion
1 Thoughtseize
1 Stubborn Denial
1 Dismember
1 Whipflare
2 Anti-Eldrazi cards
1 Grafdigger’s Cage

You can fill in the rest, which could be more copies of cards in the list above or different cards, based on your own metagame expectations and personal preferences. I have no strong recommendations for those remaining slots.

I’ll go over the matchups later in the week, so check back here on ChannelFireball for the sideboard guide.


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