The Science of Sideboarding

There are people who will tell you that sideboarding is an art, but I like alliteration in my titles.

While many people play the same decks as each other, there are also many reasons that some players succeed with those decks while others don’t. One of the things that sets the winners apart from the losers is the ability to build strong sideboards and make good decisions when sideboarding. Despite the importance of sideboarding, it often overlooked completely during playtesting. Given that at least half of your games will be after sideboarding, this is usually a big mistake.

There are two phases to optimal sideboarding. The first step is building your sideboard properly, and the second step is using it to best effect. There are several things to consider when building your ’board and deciding how to use it.

Should I Build a Transformational Sideboard?

Typically, the answer is, “No.” This is a strategy for one-dimensional decks or decks that are either very vulnerable to other people’s sideboards or a specific deck that is really popular. Most frequently, this plan is used for making combo decks into creature decks. If you’re playing a creatureless Stasis deck and you play against a deck likely to swap in a ton of enchantment and artifact removal in place of creature removal, it’s nice to be able to switch gears by bringing in creatures to steal a win.

While I rarely use this strategy, it was very effective for me at GP: Denver in 2001. I played a creatureless control deck that had Undermines and Urza's Rages as my only sources of damage. I could also reuse them with Yawgmoth's Agenda. My other path to victory involved decking my opponent with repeated use of Lobotomy. I had several creatures in my sideboard for two reasons. First, the best cards in the format were Repulse and Exclude. My deck was better in Game 1 because my opponents’ copies were dead cards. In Game 2, I could punish them for removing those cards by bringing in creatures. The other, perhaps more important, reason was that my deck was slow, and I frequently needed to win quickly after sideboarding. I actually didn’t lose a match in Day 1, but I still barely made Day 2 because I had so many draws. Fortunately, my creature-heavy sideboard helped me win all of my Swiss matches on Day 2 to squeeze me into the Top 8, in which I lost a tight match to the eventual champion in the semifinals.

Do I Have a Way to Take Advantage of Silver Bullets?

I’m not usually a big fan of single copies of cards in my sideboard. There are some big exceptions, though. If I have a way for my deck to search for specific cards, suddenly having single copies of cards in my ’board goes from a questionable idea to a fantastic idea. Over the years, I’ve played with Survival of the Fittest in lots of decks. In those decks, I was sure to have a lot of single creatures in my sideboard. I was able to use Survival to search for whichever creature would help me the most in a given situation. Sometimes, there will even be a specific card that will blow a specific matchup wide open if you draw it. These are referred to as “silver bullets.”

Jon Finkel is among the kings of the silver-bullet sideboard. At US Nationals in 2000, he played a mono-black deck with Vampiric Tutors. His sideboard looked like this:

Every matchup he faced, he was able to bring in a couple cards that he could tutor for to take control of the game. He was able to ride this strategy all the way to becoming the Nationals champion. His sideboard for the deck he just drove to a Top 4 finish in Hawaii looked like this:

In this deck, it was a less obvious choice to be sideboarding so many single copies of cards. Jon’s explanation for it was that the deck “saw so many cards” with Ponder and Gitaxian Probe. He even had three one-ofs in the main deck. He also made the point that while for every situation there was an optimal card to draw, many of his cards were similar enough that he actually had multiple cards for each situation.

How Can I Beat My Worst Matchup?

When developing and testing a deck, it’s important to figure out the deck that you’re likely to run into that will give you the most problems. Obviously, if the matchup is really bad and you expect to see a lot of it, you may want consider a different deck. Once you’ve identified your bad matchup, it’s time to decide how to address it with your sideboard. Ask yourself a few questions. Are the rest of your matchups good enough to allow you to devote most of your sideboard to the bad matchup? Is the bad matchup bad enough and rare enough that you shouldn’t even bother addressing it? Is it bad enough and common enough to justify a transformational sideboard? Ideally, you can focus a large portion of your sideboard on your worst, common matchup while using cards that are versatile enough to also be helpful in other matchups.

How Many Cards Can and Should I Take Out?

One of the most common sideboarding mistakes is oversideboarding. It’s very important not to make holes in your maindeck through sideboarding. This comes up frequently with high-level decks—one of the hallmarks of top-level decks is that they are very tight and focused. Deciding what to take out is an underrated skill that can require quite a bit of creativity. What you take out is almost as important as what you put in. I’ve frequently heard less experienced players say, “I had a bunch of cards I wanted to bring in, but I couldn’t decide what to take out, so I didn’t end up sideboarding.” This is someone who didn’t do enough preparation for an event.

Alex Bertoncini is an example of a creative sideboarder. When playing Red Deck Wins against Alex Bertoncini’s control deck, I played around Mana Leak every game. It was only after the tournament and being eliminated by Alex that he informed that he’d taken his Mana Leaks out against me. If you feel your sideboarding needs improvement, consider making a list of cards to bring in and out in each matchup before the event. Don’t be embarrassed to refer to it when sideboarding either. I’ve even seen Finkel do it at Worlds this year.

Are There Any Matchups That I Can Ignore?

The most obvious matchups you can ignore with your sideboard are the ones that you’ve determined you’re unlikely to see at the event. More important, however, is determining which common matchups are so favorable that you’re deck doesn’t really need to be changed against. If you don’t have any matchups like this, you might be playing the wrong deck. When deciding what deck to play, you should be picking a deck that has at least one really good matchup that is a big part of the metagame.

Should I Always Sideboard a Given Matchup the Same Way?

Not necessarily. There are three main reasons to shake things up sometimes. The most obvious reason is that what you’re doing isn’t working. The fact that you’ve made a plan and written it down doesn’t mean you have to stick to it. Perhaps you’re up against a different version or a version with a sideboard that’s good against your original plan.

The second reason is that, sometimes, you might want one plan going first and another plan when you’re drawing. For example, if you’re playing control against aggression, perhaps you want your Mana Leaks when going first but not when you’re going second.

The third reason is to keep your opponent guessing. This comes up frequently with transformational sideboards. If your deck was all about enchantments in Game 1 and all about creatures in Game 2, you may want to switch back in Game 3. If people know that you normally take your permission out in a matchup, perhaps you should change it up.

It’s important to remember that your efforts to build the best sideboard will be seriously hurt if you don’t have good intelligence about the metagame. Since this is also true about your deck choice in general, you should always make sure to research the metagame before building your deck and sideboard. This usually isn’t that hard in Standard. If you look at the decklists of the decks that are going 4–0 in Magic Online events, you’ll usually find they consist of a pretty small number of archetypes, and the lists for a given archetype are usually remarkably similar. Once you know what you’re up against, you’re ready to build your sideboard. Just make sure to take my questions into account when you do.