Modern is a format with an almost limitless number of viable decks. It’s difficult to make generalizations about a format like that, but I’ll make one anyway: Affinity is the signature deck of the Modern format.

Affinity was there on day one and has never really relinquished its hold on being an undeniable tier 1 strategy. When people tell you that Affinity is well positioned, it probably is. When they tell you it’s poorly positioned, it isn’t.

The fact is that Affinity is just an all-around great Modern deck. It’s fast. It can do a lot of things. It cheats on a bunch of different axes.

I decided to go back to my roots and play Affinity at the RPTQ last weekend. I made Top 8, but lost to my friend Max McVety in the quarterfinals. The deck was solid for me all day and I was bummed out that my Top 8 match against a strong opponent was the moment when my deck decided to punk out on me and not function properly.

With that being said, Modern is a format where you “go big or go home.” I played and watched a lot of games, and I was kind of shocked at how many games appeared to be decided by non-functioning draws. With that being said, Affinity is one of those decks that I believe has a high function rate—it doesn’t just crap out too often.

Stock Affinity

Brian DeMars

There is nothing too crazy going on here. I’m not trying to reinvent the wheel—I just want my deck to be powerful and consistent, and the Affinity list is close to a solved commodity.

There are a few flex spots in the deck that people go back and forth between. How many Master of Etherium vs. Etched Champion in the main deck? How many Galvanic Blast vs. Thoughtcast, etc.

Most lists play 3 Spire of Industry and 1 Glimmervoid. I lost my Glimmervoid to a Hurkyl’s Recall yesterday and it cost me the game on the spot. I’m so over Glimmervoid. All Spire, all the time.

With that said, I’m happy with how this list is positioned with regard to the distribution of spell choices. I’m also really happy with the sideboard and the overall sideboard strategy.

Sideboard Guide

I’m a huge fan of sideboard guides, but I realize they have shortcomings.

First of all, decks change and people adapt. Second of all, I don’t believe in “right” and “wrong” when it comes to playing Magic. I don’t always do the same thing. I leave room for innovation and improvisation.

As long as we understand that sideboard guides are not a perfect science, they are terrific. They are a great way to cover a lot of ground when learning a new deck (which is where I think they are most valuable) but they are also a nice way to see how different players approach different matchups.

I’m going to go over a few of the key matchups. If I don’t cover the specific matchup you are interested in, let me know in the comments, and I’ll respond there. With that being said, these are some of the matchups I’m most interested in being prepared for.

One important note about sideboarding with Affinity in a situation where you may be unfamiliar: One of the biggest mistakes that people make is to sideboard into a deck that is likely to be non-functional. There are a ton of awesome colored spells in the board but you still need to be an artifact aggro deck at the end of the day. In an ideal world, you’d like to stay between 8-10 colored mana spells after board. Anything more puts you in danger of drawing into a hand that might not work!

You only have 13 sources of colored mana (and one is a basic Mountain…).

The Mirror Match

Affinity is one of the most popular decks in the format, and so knowing what to do in the mirror is important since you’ll likely play against it a lot.



The matchup becomes really grindy after sideboard. The deck can still run somebody over—but that’s more a symptom of a strong draw matching up against a weak one than the typical dynamic of the matchup.

All the removal comes in and you board out the weakest creatures to make room for it.

The latest swap that I made to my list was to cut the second Ancient Grudge for a Natural State. The main reason that I made this switch was that I wanted the Natural State against Ad Nauseam as an answer to Phyrexian Unlife. While losing the Grudge is an overall downgrade against the mirror, it is worth noting that Natural State answers Aether Grid and Bitterblossom, which are powerful mirror breaker cards that cannot otherwise be answered.

The Storm Match

Storm is a difficult matchup. Game 1 is not favorable and it doesn’t get much better after board. They don’t really need to interact with you in order to win because they are faster, which means that you need to interact with them. On top of that, they have access to a bunch of really insane sideboard cards that absolutely wreck you: Shattering Spree, Hurkyl’s Recall, and Shatterstorm.



I want everything that interacts with their Stormy stuff and I want to be as mana efficient as possible. You don’t need the haymaker creatures so much as you need interaction and a clock.

Rule of Law is the best route to victory, and it is important that the card is not an artifact and isn’t easily answered by Shatter effects.

Collected Company Combo

Collected Company feels like an even matchup. Their best way to defeat you is the combo, and so answering a Devoted Druid is really important because it is hard for them to win without it.

After sideboard, you can expect them to have more removal, but also some messed up sideboard cards. Be aware of Chord of Calling for Kataki, War’s Wage.

I try to become more controlling in this matchup because I believe Affinity has inevitability as long as they can’t combo me out.



As long as you can keep the table clear of the combo there is a good chance that you will win. The new CoCo decks are much less efficient at beating down than the traditional Abzan lists. Your creatures fly and they are pretty bad against flyers.

There are certain matchups where I like to shave a Cranial Plating. There are a lot of people who hold strong to a “never board out Plating on principle because the card is simply so powerful” ideal. I understand this logic, but I don’t agree. While the card is awesome, it isn’t the most important thing in some matchups. Drawing multiples in a tight matchup can cause some problems.


Burn is another close matchup. Overall, the matchup favors Affinity but it varies wildly from game to game because the individual games tend to be very lopsided one way or the other. There are more “kinds of games” where Affinity is favored. But play and draw are a big factor.

If the Affinity can spew their whole hand quickly it will be hard for Burn to race. It’s all about tempo, folks, and Affinity is designed to play at a breakneck pace!



Steel Overseer is an awesome card but it is just too slow and poorly positioned in the matchup to stick around. Expect the Burn player to overload on spells that kill a creature and deal damage to the face:

The Champions are nice because they are immune. Spell Pierce is great because it can counter their sideboard cards. You don’t need to work very hard to make a Spell Pierce a blowout against Burn!


The new Human tribal deck is all the rage right now, and so knowing how to fight it is key. Overall, I think Affinity has a nice matchup here because it is all about racing, which is where Affinity shines.



One of their better cards is Reflector Mage and I don’t want my 3-drop to get wrecked by their 3-drop, which is why Master of Etherium is replaced by Etched Champion.

The Champions do a lot of work in this matchup since they can block giant ground pounders and wear a Cranial Plating into the red zone.

The Takeaway

There are obviously diminishing returns on trying to list every Modern matchup. But the best way to make sense of the sideboard is as follows:

You are typically doing one of the following (COLUMN A):

  1. Boarding in disruption to stop a combo.
  2. Boarding in removal against creatures.
  3. Boarding in Etched Champion against removal.

You are typically boarding out creatures to make room (COLUMN B):

  1. Boarding out expensive creatures to lower the curve.
  2. Boarding out Master to balance colored requirements.
  3. Boarding out a creature that is tactically weak in a matchup, e.g., Overseer vs. Burn or Signal Pest/Champion in the mirror.

If you can identify which of the three you need to do from column A and match it against column B you’ll make good decisions even if you have to make choices on the fly.

Sideboarding is important and it is something that I’ve been working on being better at lately. Games are won in the trenches.

If there are specific matchups that you’d like to talk through, be sure to drop those into the comments section. I’d love to work with you all to refine and improve your plans with Affinity against the field.

The deck is already great. The better the choices you make the better the payoff.