Many people will spend hours and hours working on and testing their main deck, but piece together the sideboard of their deck the morning of the tournament. Why do they do that? If you think about it, you’re going to be playing more games with a sideboarded deck than you would with your mainboard.
The sideboard is an often neglected piece of artwork. Its composition depends on your mainboard, and because of that, each time you change a card in your mainboard, you have the potential to be changing multiple cards in your sideboard. Because of that, the first step in creating your sideboard has to be that you need to be 100% sure of your mainboard.
Once that is complete, the rest of the sideboard should NOT just fall into place, like I’ve seen happen so many times before. Look online and see how many sideboards you can find which are full of playsets of certain color- or deck-hosers. There sure are a lot out there, and not one is well crafted.
I think that any sideboard containing more than one playset of a certain card is a sideboard which hasn’t been thoroughly thought through. Multiple color hoser cards are another indication that a sideboard isn’t as well done as it could be. Deck-hosers are okay so long as they cannot be removed by that deck. If they can be, they shouldn’t be considered “deck-hosers” but rather, “deck-delayers,” and probably shouldn’t be played. A great example of this was when the Astral Slide decks were running around in Onslaught Block Constructed, and Stabilizer was printed. It looked like a perfect fix for that powerful deck, as an artifact which shut down the entire cycling function of the Astral Slide deck. The problem was that Astral Slide decks already played multiple cards which destroyed artifacts mainboard, and the decks that decided to run that deck-hoser often weren’t fast enough to kill the Astral Slide deck before it was able to take control. What started as a sure fix eventually turned into a really poor sideboard option.
What we’ve found is that a truly successful deck runs just enough cards against a certain deck to cover the number of cards which are considered poor in that matchup. No more, no less. It doesn’t matter that a certain deck makes up ten or eighty percent of the field, you should still be sideboarding the same number of cards against that deck! If you feel that it isn’t enough, you shouldn’t be playing your deck in a serious tournament.
Color- and deck-hosers shouldn’t have a prominent place in your sideboard unless they are extremely powerful, and difficult to remove. Assume that your opponents will sideboard against your sideboard if those hosers are often played. If they can remove those hosers with any possible cards in their colors, you shouldn’t play these cards. Look at a hoser like Chill (1U, Enchantment. “Red spells cost 3 more”). This is an extremely powerful hoser, not only because it stomps on red cards, but that while it was in rotation, every popular deck which played red was mono-red, and mono-red has no way to remove enchantments. This color-hoser could be played quite easily in a format like this. Playing Chill in an environment where most red decks will splash for white or green is not a good idea, because those decks have access to enchantment removal.
So where do you turn for sideboard cards. Certainly, you can look to a few of those hoser cards for some slots. Exploit the weaknesses which decks have, especially against control decks. Beatdown decks can always slow down, but control cannot speed up without making it extremely weaker. Try to speed yourself up and see if you can find uncounterable or untargetable creatures, as these will put a clock on your opponent, and force them to try to win quicker, weakening their strategy.
Against beatdown, you should try to slow them down, either with creature kill, delay cards (like Fog or Orim’s Chant), big creatures, and even Walls in a pinch. These cards will provide more economy, and if you can survive their initial onslaught, you should win that match. As soon as you take control, they’ll probably be done.
Combo decks are often the simplest to sideboard against, which is probably why they have lost popularity. Hosers work extremely well against them, and if you can get a quick clocking creature out early, you can usually ride your hosers to the end of the match. Any form of disruption will end the games quickly and cleanly.
Make sure that you are also prepared for mirror matchups. Many people assume that they can’t get advantage there, so they don’t even try, and that is just plain wrong. Our team had a strategy of using our sideboard for the mirror matchups to attempt to make our decks more efficient rather than trying to slow down our opponents decks. For example, we found that Oversold Cemetery was an excellent card for the Goblin mirror match in Onslaught Block Constructed format, even though it required splashing for black. It gave us lots of card economy, and didn’t substantially affect the rate at which we could play creatures. It was an easy fix to make, and while other decks were working on killing our goblins, our deck would catch them by surprise by gaining a lot of card economy and reincarnating our dead guys.
An underused option for your sideboard is to use it to change your main deck. Our team once designed a great combo deck, which was a downright auto-win against certain decks, but couldn’t handle anything with counterspells. We decided that instead of messing around with lots of anti-control nonsense, that we’d sideboard 15 creatures and try to change the deck into a beatdown deck post sideboard. Sure, it sounds strange, but we knew that those control decks which weren’t expecting us to break out some creatures, had sideboarded out their creature killers. It worked fairly well, but you need to analyze what other decks will do against your deck, and try to decide if people are ALWAYS going to do that. If there is a doubt, then you might want to reconsider doing this.
There are many options, but once you’re done considering all your options for each match, look and see where you have overlap. Consolidate cards, and hope that you can crunch your options down to fifteen. If you can, consider yourself very, very lucky, and move on to the final step. If not, you’ll need to move on to the next step.
This is the hardest part. Try to remove the cards which are only good against one matchup. If you can use other cards from other matchups for the same purpose, use them. If you see cards which do similar things against different decks, see if there is another card you can use in place of both. The idea here is take advantage of all your options, without screwing up your sideboard with cards which are too specific. It is rare that a format is so specific where there will only be two or three powerful decks, so it is necessary to diversify.
Now that your sideboard is basically complete, you simply need to memorize the matchups, and check to make sure your mana curve will be acceptable in your matchups post-sideboard. With that done, you should have a very diverse sideboard, and it’s likely that there will be a lot of 2- and 3-ofs, and only a rare 4-of. This is good! Look at the sideboards the pros are playing, and you should see that they typically run these kinds of random-looking sideboards. In fact, these are as well crafted as you can get. Creating a well-thought-out sideboard like this is one of the major keys to success in winning major Magic tournaments.