As a general rule, people love sideboard guides. Whenever I write about a deck, the first reply is usually either “Thank you for the sideboard guide!” or “Where is the sideboard guide?” I understand the appeal—we certainly don’t want to risk having to make a decision on the fly and being wrong if it’s something we can already memorize or write down beforehand.

That said, you should know that sideboard guides are only guidelines, and not hard rules. They are meant to give you an idea of what is good and what’s bad in the matchup, and not to serve as a replacement for thinking. There are many tournaments I play in where I sideboard differently against every single one of my opponents, depending on one factor or another.

Today, I’ll talk about the factors that should lead you to sideboard differently than you normally do. I’m not saying that you should do away with sideboard guides—I use them too—I’m just saying you should not stop thinking just because you have a sideboard guide. For me, there are three main characteristics that will make me deviate from a guide:

Are You on the Play or on the Draw?

This is the most common factor, and some authors even incorporate it in their sideboard guides. I try to do this when the difference is striking and the matchup is very common. That said, it’s not done nearly enough. There’s a world of difference between being on the play or on the draw, and it’s very likely that you want a different configuration for each one.

As a general rule, whenever you are on the play, you’re able to execute your own game plan. When you’re on the draw, you’re forced to react to their game plan.

Let’s take, for example, a combo deck: B/R Reanimator in Legacy. B/R Reanimator is very much an “all-in” deck—you’re trying to win on turns 1 or 2 most of the time. If you’re on the play post-board, then your main plan is still the same—you’re trying to brute force a combo before they can cast a hate spell, and you don’t want to dilute your deck too much because the new plan is the old plan. You can, for example, win the game before a Deathrite Shaman loses summoning sickness, or before they can play a Counterbalance. If you’re on the draw, however, you have to accept that you might not be able to combo immediately, and you change your deck a little to reflect that. This might mean, for example, adding Grim Lavamancer to deal with Deathrite Shaman, or perhaps taking out some combo pieces and bringing in a couple of Reverent Silences to deal with Counterbalance.

In Standard, we recently had a very good example of this in the Temur mirror. Whenever you were on the play, the best strategy was to execute your own game plan—you wanted to play Servant of the Conduit or Longtusk Cub on turn 2. If you were on the draw, however, you couldn’t afford to let their 2-drop live—you had to kill it. Your own game plan would just be too slow, so you had to become more reactive and stop theirs. This meant that, on the play, we had Longtusk Cubs in our decks, but on the draw, we had Abrades instead because we would want to Abrade their 2-drop anyway. On the play, we were proactive but on the draw, we tried to be more disruptive.

This also happens with control decks versus aggro decks, where the control player can usually afford more slots dedicated to card advantage if they’re on the play than if they’re on the draw. If you’re paying U/W and you’re on the play versus R/B, you’re fine having Search for Azcanta in your deck post-board because there’s little you’d want to do on turn 2 anyway—they haven’t done anything, so you don’t have to react to it. This means that you are free to just execute your own game plan, and play your card advantage engine on turn 2. If you’re on the draw, things change. Suddenly, playing a Search for Azcanta means that you didn’t cast Seal Away on a Scrapheap Scrounger or a Kari Zev, Skyship Raider. It also means that you couldn’t Essence Scatter or Syncopate a Goblin Chainwhirler or Pia Nalaar. Often, it means both of those things, and you’re just too far behind. A lot of the time you have Search for Azcanta in your opening hand versus B/R. If you’re on the draw, you can’t even play it on turn 2 because you have to react to what they are doing. At this point, I’d rather just not have them in my deck.

The same is true for most counterspells. If you’re on the play, you can afford to counter things every turn. If you’re on the draw, then you will often have to react in some other way to permanents that are already in play, which means that you won’t be able to keep mana up every time. Because of this, cards like Disallow are much better versus aggressive decks on the play than on the draw, because you can afford to keep 3 mana up on turn 3 if you’re on the play, but you cannot do that on the draw.

You also have to pay attention about your mana curve. If you’re on the draw, your 3 mana cards have to match up well against their 4 mana cards, whereas if you’re on the play, then you have to match their 3 mana cards. This is very important for counterspells. For example, if your opponent has 3 mana cards that you’d like to counter, then Disallow will be good enough on the play but not on the draw. If I’m playing U/W against R/B, then I think Disallow is a better card than Essence Scatter on the play (since it can counter Chandra and Karn), but I have Essence Scatter over Disallow if I’m on the draw because I want to be able to counter Pia Nalaar and, to a lesser extent, Goblin Chainwhirler.

If you’re on the draw, cards that catch you up are usually better, whereas if you’re on the play, then 1-for-1 answers are often good enough. For example, if I’m on the play versus an aggressive deck, I might not need all of my Settle the Wreckages and Fumigates—I plan on countering or killing every creature they play anyway. If I’m on the draw, I might not have the time to counter or kill every creature they play single-handedly, at which point I need a sweeper to get back in the game. Therefore, I could reasonably take out sweepers on the play and add sweepers on the draw.

Another type of card that gets much better on the play is planeswalkers. Planeswalkers thrive on being played into an empty board (or an advantageous board), and if you’re on the play you’re much more likely to have an empty board by the time you play them. If you’re playing an aggressive deck mirror, then it’s common to have many planeswalkers on the play and few or none on the draw. We did this with Chandra, Torch of Defiance in Red mirrors, for example, or with Nissa, Steward of Elements in the Temur mirror. If you were on the play, you could often play Nissa and plus it, and your opponent wouldn’t have a way to kill it. On the draw, they’d already have a Rogue Refiner or a Whirler Virtuoso in play, both of which represented lethal damage to Nissa, which meant that it wasn’t worth it.

This is also true in Limited. Take, for example, our last GP Top 4—Dominaria Draft. We were 3rd in the Swiss, so we knew that we were going to draw first in our matches (since whoever is higher seed gets to choose and everyone chooses play). This impacted our drafting and deckbuilding decisions – we knew, for example, that we might want slightly more defensive cards, as not to fall behind early – cards like Caligo-Skin Witch and Fungal Infection rose in priority a little bit. Ben was talking about how he really likes Dark Bargain in the format, but he wouldn’t prioritize them in this draft specifically – he would specially not highly pick a second one, because he wouldn’t even play two in his maindeck on the draw, whereas if he was guaranteed to be on the play, he’d both pick and play two.

Another thing you can do if you’re on the draw is take out a land, because you’ll have an extra card to find your land drops. Imagine this scenario:

You have a 25 lands, 60 cards deck. You want to make your first four land drops. If you’re on the play, you’ll see 10 cards. The chance of finding at least four lands is 67%. If you’re on the draw, the chance is 76%. If you cut a land on the draw, then the chance is 72% – still more than with 25 lands on the play. In fact, you could even cut another land, down to 23, and you’d still be more likely to hit your first four lands on the draw than with 25 on the play. Of course it’s not as clear cut, as you’re more likely to mulligan with fewer lands and whatnot, but even if you do have to mulligan, it’s not as bad if you’re on the draw.

How Do They Play?

Each person will play the game in a different way, and sometimes you can exploit that by sideboarding differently, either because you know them and their style or because of something they did in games 1 or 2.

For example, at GP Toronto I played against Martin Juza. I was playing U/W Cycling and he was playing Red-Black. I have played versus Martin a lot before, and I know he is extremely conservative and will go to great lengths to not be blown out by certain cards. In game 1, he confirmed this by attacking into Settle the Wreckage with only one creature, when most players would attack with two. So, in game 2, I took out all Settle the Wreckages. This is not what I usually do against R/B decks (at least on the play), but I knew he would play against them all the time, even potentially in a spot in which he shouldn’t, so their value would be greatly diminished. Now, if Martin had been playing Mono-Red, then I would have kept them in anyway because you just need them, but against a very conservative R/B player I felt that I could do without them.

I was able to do this because I know Martin, but you don’t necessarily need to. One of my favorite sideboarding stories is from when we were playing U/G Scapeshift, and our plan was to take out Jace, the Mind Sculptor against Zoo because it died too easily. Then, when Gabe Walls played against a guy in the GP, he realized in game 1 that the guy wasn’t actually attacking his Jaces. Jace was a good card and the only problem was that it died easily, so if the opponent wasn’t killing it, then it was just a good card. Our sideboarding sheet said: “Vs. Zoo: -2 Jace, the Mind Sculptor”, but Gabe not only kept the main deck Jaces but he actually added a third Jace from his sideboard, just based on the way his opponent played.

What Does Their List Look Like?

Lists are almost never identical to each other, and it’s a mistake to sideboard in the same way versus two decks only because they are the same archetype. Take, for example, mono-red splashing Scrounger and mono-red without it. Both decks are “mono-red”, but you should sideboard differently against them. If they have Scrounger, then I like Forsake the Worldly, and I’ll board into multiples, but I don’t like Fumigate. If they don’t have Scrounger, I don’t like Forsake the Worldly and I like Fumigate. What if they have Scrounger but don’t have any other artifacts? Well, then I’ll evaluate on the fly, but the important thing is that I’ll actually think about it, rather than just following the guide blindly.

The same is true for mono-green. You might have “mono-green” in your sideboarding sheet, but what happens when they are splashing for Scrounger? Or for blue cards? Clearly, there’s a chance that your plan will be different, but people often fail to adapt to that.

I was a victim of this at the last PT. I was playing the U/G Karn deck, and we had sideboard plans for B/G Snake. I then played against an opponent who was playing a much more planeswalker-heavy version of B/G. He didn’t actually have Snakes—he had his own Karns, Nissas, and Vraskas. I looked at a B/G deck in front of me and I sideboarded like I sideboarded versus B/G Snake, which included bringing in two Baral’s Expertise, which were just incredibly awful against his deck. I should have realized the differences in his deck meant that my sideboard guide versus B/G wouldn’t really apply, and I shouldn’t have sided that card in.

Another example: In PT Kyoto, we played Mono-Red and we had a sideboard plan that we thought was pretty good and included removing Village Messenger (everyone did this) and going bigger than our opponent. Then, in the quarterfinals, I played versus Seth Manfield. We knew his deck list because it was the Top 8, and we saw that he had the ability go to even bigger than we did. At the same time, he had no sweepers, no Pias, and no way to punish us from going wide (we had Pia and Savage Alliance to stop him from doing it, for example). Because of this, we decided to deviate from our plan. Instead of taking out the 1/1s and Ahn-Crop Crashers, we just kept them all and tried to go under him. In our sideboarding sheet, we were assuming mono-red players would have ways of punishing us for having many small creatures, but once we knew that he didn’t, we could adapt and deviate from it.

Bonus: Do You Have Enough Time?

This only affects a subset of decks, but sometimes the time on the clock will make me deviate from my plan. If I’m U/W, for example, I don’t normally board History of Benalia in against U/B Midrange, but if I have 5 minutes on the clock, then I might go ahead and do it because I know I won’t win in 5 minutes with just four Teferis. It rarely comes up, but I feel that I should at least mention it.

So, to sum it up—do read sideboard guides, but don’t be a slave to them. Know they are only guidelines, and that you should deviate based on what’s happening in the match, your opponent’s list, and how they play.