In this article I will be discussing some aspects of sideboarding from a deckbuilding point of view. Sideboarding plays a very important role because for every maindeck game there will be at least one sideboarded game in the match.

For this reason, I think we should all spend far more time on it than we currently do. This is not a comprehensive guide, but if you follow these five steps you should be a lot closer to building better sideboards and understanding how to do it correctly.

1. Building a Post-Board Deck

I quite often see people simply exchanging cards that are good for cards that were bad. This is a mistake in that they’re not paying attention to what their deck will look like with these changes. Let’s say you’re playing Esper Control versus Delver in Standard. You know that you want to board in Timely Reinforcements as well as a bunch of removal. In game 1 the cards that weren’t great were the counterspells and the draw spells. Think Twice and Forbidden Alchemy are so expensive that you couldn’t afford to cast some of them let alone flash them back.

You replace your Mana Leaks and some of your draw spells with an additional Day of Judgment, three Timely Reinforcements, two Phantasmal Images, and a pair of Ratchet Bombs. In game 2 you were easily able to kill all of their early threats, you went way up on life, and you even Ghost Quartered their Moorland Haunt. The game went super long, and for some reason you just kept drawing lands and more removal and eventually they got there with some random spirits.

The mistake here is that you took out your draw spells.

Post-board you have cheap ways to gain tempo back, and this gives you the time to cast your draw spells, making sure that you have enough gas to finish them off (even if they have countered your Elesh Norn, Grand Cenobite). Your deck contains considerably more lands than your opponent and far fewer threats. For this reason, the draw spells are required in order for your low threat density to overcome their Dissipates and Phantasmal Images. Timely Reinforcements, Ratchet Bomb, and Day of Judgment all offer excellent card advantage but don’t actually finish the job.

The distinction should be made here between card advantage and card draw. The way I see it, these are two very different things. Let’s define and compare interactive card advantage and non-interactive card advantage (card draw).

Interactive card advantage means exchanging a number of your cards for a larger number of theirs. This type of card advantage dramatically reduces the effectiveness of their draw, giving you more time. You can also gain mana advantage, as the mana you spend will result in your opponent needing to spend mana. Interactive card advantage, however, can be offset by your opponent’s card advantage. For example, the advantage gained from Day of Judgment can be offset by a Snapcaster Mage or a Moorland Haunt.

Non-interactive card advantage, or card draw, exchanges one of your cards for multiples of your cards. These can be chained together and result in you digging further into your deck. It’s often possible to chain these continuously until you’re able to win the game. Card draw can often include card selection. Forbidden Alchemy is a prime example which further increases the chance of chaining them as well as finding you specific answers. Non-interactive card advantage cannot generate a mana advantage; in fact it does opposite. It finds more of your cards for which you must spend more mana.

In the example above, the sources of interactive card advantage in Timely Reinforcements, Day of Judgment, and Ratchet Bomb are far cheaper than the non-interactive card advantage, and it seems logical to replace one with the other. Unfortunately, they are not directly interchangeable. If you’re playing a deck with many lands and few win conditions, dramatically reducing the effectiveness of your opponent’s draw will not help you to find your win conditions in the same way that a card like Forbidden Alchemy does.

A deck full of card advantage and no card draw might not be a good deck if its threat density is too low. After you have your sideboard plan worked out, look at the 60 cards you are about to present and work out if it’s still a good deck and if this deck is the best deck you can present.

2. Knowing Whether a Matchup Needs Help

An important thing to know before you address your sideboard is how the deck fares against the top tier decks. You only have access to a fifteen-card sideboard and knowing which matchups are good and which aren’t allows you to use those sideboard slots most appropriately.

A common mistake people make is to think of the four top decks and devote three or four cards for each. This is a ridiculous concept, as it will only alter your match win percentage by the quantity and effectiveness of your sideboard cards against the quantity and effectiveness of their sideboard cards. This is given that neither of you significantly changed the composition of your decks.

Once you have worked out which matchups are good and which aren’t, you can begin to address them. Sometimes a matchup is bad enough that it can’t be fixed. For example, if you are an 80-20 underdog game 1 and the best you can get in game 2 is a 50-50, then you’re still very unlikely to win the match. It’s possible that it’s not worth the sideboard slots it will take to get it to this point. This is based on the reasons why the matchup is bad and the effectiveness of potential sideboard cards.

For example, take my Modern U/B Fish deck versus Affinity. The game 1 matchup was horrendous, as their game plan was excellently positioned against mine. I had tempo cards and disruption that wasn’t effective against their threats. Vendilion Clique looks embarrassing in the face of Inkmoth and Blinkmoth Nexus. Sword of Feast and Famine does nothing, and Cryptic Command was too slow.

Post-board, blue and black don’t have access to things like Ancient Grudge and Kataki, War’s Wage. The best you have access to is Hurkyl’s Recall and possibly Steel Sabotage, but that doesn’t do too much if you’re unable to take advantage of the time that it buys you. I realized the matchup wasn’t fixable and decided to side in cards that I had for other matchups and try to get lucky.

Engineered Explosives was often too slow and sometimes didn’t do much at all, but other times you could get a four-for-one and win the game. Threads of Disloyalty isn’t great but occasionally you could steal a Vault Skirge that had a couple of +1/+1 counters on it or had been made into a 5/5 with Tezzeret, Agent of Bolas.

The matchup was bad enough that I didn’t want to devote sideboard slots to it, as it wasn’t going to massively change my chance of winning the matchup. Even if I was able to steal games with my makeshift sideboard, my plan for the matchup was to hope to not get paired against it. If Affinity is a large enough portion of the metagame and I was sick of losing to it, then I would choose not to play U/B rather than try and fix it with the sideboard.

Once you’ve decided which matchups you’re going to address, you then need to work out how many cards you will side against each. This should be based on the effectiveness of dedicated sideboard cards, the strength of versatile sideboard cards, and the amount of cards you need to sideboard out to reach your desired post-board deck.

3. Different Types of Sideboard Cards

Some sideboard cards are high impact. Going back to Standard: Celestial Purge against Zombies; Ancient Grudge against Tempered Steel; Curse of Death’s Hold against Delver; Act of Aggression against Frites; and Timely Reinforcements against red decks. High-impact cards will make the largest difference in your game win percentage.

If you want to significantly improve a matchup, this is usually achievable if you have access to this sort of card. High-impact cards are usually (but not always) narrow. If you don’t get paired against the deck they’re for, then you won’t use a portion of your sideboard.

Sometimes you don’t have access to a high-impact card, sometimes that card won’t fit your strategy, and sometimes you’ve decided not to dedicate spots to a specific matchup. In these kinds of situations you’ll be looking for versatile options. Cards like Thrun, the Last Troll, Phantasmal Image, Arc Trail, Oblivion Ring, and Ratchet Bomb usually fall in this category.

Versatile cards are usually cards that suit your deck well; they fit in the curve and don’t conflict with the deck’s goal. They won’t always win the game on their own, but they will do a good job of replacing bad cards and generally increasing the effectiveness of your deck.

Sometimes these versatile cards are high-impact cards in some matchups while still being good in others. For example, Timely Reinforcements is awesome against red but is also good against Zombies, Delver, and Tempered Steel.

4. Figuring Out The Number of Cards to Side Out

A key rule of sideboarding is to always have enough cards to replace those that you don’t want to be in your deck for games 2 and 3. When you’re working out sideboard composition, you should always go through the top tier decks one by one and work out which cards you want to side out. A well-tuned sideboard should be able to replace all bad cards in each matchup while still having access to some high-impact cards.

The key goal of sideboarding is to improve your match win percentage by as much as possible across the board. Sometimes this conflicts with the above rule. This usually happens when a top tier deck is either a very good or a very bad matchup.

If a matchup is good, it can be ok to not be able to side out all your bad cards as you will probably beat it anyway. As previously mentioned, sometimes you’ll decide to just ignore a matchup. Trying to eliminate bad cards is a great step to take and you should definitely do it, but you shouldn’t compromise your main goal. Fortunately, most of the time you won’t have to.

5. Sideboarding for Their Sideboard

The last sideboarding area I want to talk about today is one that is tied closely with game theory. With a background in economics, I have found game theory to be valuable in Magic games as well as in deckbuilding. For those without an understanding of it, game theory in Magic terms means trying to work out what your opponent’s optimal play is and using this when considering yours.

With regard to sideboarding, this means that you should try and work out how they will board and make your decision on this rather than on the composition of their pre-board deck. This is hugely beneficial when their plan changes, but it can be applied to any sideboard decision where you have knowledge of their changes and therefore in building your sideboard in the first place.

When playing Frites, you know that a lot of people playing black will side in Nihil Spellbomb, and a lot of decks with Snapcaster Mage will side in Surgical Extraction. Decks that are neither blue nor black usually won’t side in graveyard hate. When you know that they’re bringing in graveyard hate you want to reduce your reliance on your graveyard, as you will lose a lot of card advantage and tempo when they interact with your graveyard. You can do this by siding out a couple of Unburial Rites.

This is something you would never do if you only addressed their pre-board deck. If you’re playing a deck like Frites and you expect a lot of people to side in a particular way, then your sideboard should allow you to reduce your vulnerability to their changes. In Frites terms, this means siding in cheap cards that interact with your opponents that allow you to get to the point where you can hard cast your Reanimate targets.

The mono-green deck that I built for Worlds 2010 brought in two Dread Statuaries in nearly every matchup. I discovered early on that nearly all of the top tier decks were bringing in sweepers and additional spot removal. My one-mana Elves weren’t providing mana as reliably in game 2. I also wanted to have greater threat density and resilience, and since speed was less of a factor, Dread Statuary was the perfect fit. This was my most used sideboard card, and I would never have even thought to have sideboarded it against a single opposing maindeck.

Often you won’t know how people will board against you, but you should be willing and eager to evolve your sideboard as you learn more about your deck and your opponent’s plan against it. Sideboarding is difficult to do well as there are a number of factors to consider. If you do it well you can gain an advantage against anyone who doesn’t, and if you do it poorly it can be catastrophic.

I hope this article helps to explain and simplify this important and undervalued tool of Magic. As always, I look forward to your feedback.

Dan Unwin

Sledgesliver on Magic Online