Sideboarding is an important part of Constructed Magic, but it's just as relevant in Limited. Sealed Deck is unique from other formats in that the sideboard is always going to be bigger than the deck itself. Recent Magic sets contain a relatively high density of quality, playable cards, which makes the sideboard more important now than ever before.
While building the maindeck is quite difficult given the number of options, and players often make mistakes, with some practice it's possible to sideboard drastically, such as swapping out an entire color or even to sideboard into a whole new deck altogether. How and when to sideboard in Sealed is a tricky and delicate issue, and today I'll discuss some of the common sideboarding scenarios encountered.
Fixing the Maindeck a.k.a. The Misbuild
Because most sealed decks can be built in various ways initially, sideboarding plays a large role in Sealed. Beyond figuring out the base colors, you also have to select which cards to play in those colors. It's realistic for a two-color deck to have upwards of 30 possible playables, so whittling this down into the best deck is not always as simple as it may seem. Especially when the build clock is ticking down.
It's very, very common for a Sealed decklist to be submitted without being perfect. The pilot plays the first game, maybe the first match, maybe more, but they soon realize some cards are out of place, and perhaps some cards in the sideboard were shoe-ins for the maindeck.
Another common scenario is for friends to share lists between rounds, criticizing, tuning, and tweaking the builds, sometimes outright rebuilding them. The player then has a plan to fix his deck after every game one. In this misbuild scenario, sideboarding has the function of fixing the initial decklist so it's fighting on all cylinders during games two and three.
An important note about sideboarding into a pre-planned "fixing the maindeck" configuration is to keep in mind that the ideal build won't be the same against every opponent, so keep specific sideboard cards in mind. Certain niche cards, such as specific color hate, artifact or enchantment removal, answers to flyers, etc., may need to come in instead of other options.
The Color Swap
Sometimes one color in your pool will be very deep in quality, making it the clear core of the deck. What color to use as support may not be as obvious.
Usually multiple colors will have their advantages and disadvantages, but only being able to choose one, the rest of the colors are left on the sidelines. Against certain opponents, the initial support color will fall flat compared another. Sideboarding can be used to swap out one support color in order to better position the deck for the rest of the match.
When to swap out a support color will depend on the texture of the pool. A recent example I experienced was in Vintage Masters Sealed Deck. I had a strong green core, but I could support it with blue or red. I went with blue, which was full of tempo-generating creatures and some card advantage. I reasoned that this was solid plan and would be strong against opponents who were likely packing plenty of large creatures paired with removal spells. When I went up against aggressive weenie decks, I opted to swap out the blue for red, which offered me less long-game potential but plenty of cheap burn spells to manage my opponent's creature rush.
These two cards were not great in the maindeck, but were extremely powerful and efficient removal spells against some opponents, and as uncommons would sometimes be seen in duplicates. If accompanied by enough quality playables, these hate cards could be swapped in along with other cards in the color and take over the support role against susceptible opponents.
The deeper the core color is, the easier the color swap becomes, simply because less cards are required to pull it off. If the color swap seems like a possibility, take a good hard look at each color and what it has to offer, and see how it interfaces with the core color. Figure out what all the possible deck configurations look like, and against what sort of opponent each configuration is ideal.
Having this all planned before matches makes sideboarding in-match simple and quick. Speed in-match is an utmost important factor, because there are only two or three minutes available for the process between games in a tournament setting.
The Deck Swap
The large card pool lead to multiple colors being deep in quality. There may not be one core color that outweighs the rest, but rather a balance between a few or more colors. Choosing which color to combine with another is not obvious, and there may even be three or four legitimate possibilities for color-combinations. In these cases, building the deck may be quite difficult, and the pilot will often be left wondering if they those the correct two.
In these scenarios, the sideboard may be left with enough playable cards to build a whole new, separate deck. In this case, pay special attention to the possibility of having an entire deck ready to be swapped in for the first one. Note that quality artifact and colorless cards make any sort of deck swap easier, as they can be a part of both builds.
The deck swap strategy allows its pilot to drastically change plans against the opponent, comparable to picking a new constructed deck within games of a Standard match in order to better position against the opponent. It's not always possible, but when it is, it can be highly effective. This deck-swap strategy also has the effect of surprising the opponent and has the potential to interfere with their own sideboard strategy.
In some cases, if your pool is relatively balanced, it might be better to go for a more complex color swap, potentially mixing and matching any combination as you see fit against particular opponents.
The Power Splash
A core theory of Sealed Deck is the power-consistency trade-off. It's usually possible to push the power level of a deck by playing more colors and more powerful cards, increasing the average card quality, but this typically comes with a very steep trade-off in consistency. There is a delicate balance usually found within two colors, sometimes with a small third splashed color if the manafixing is there.
Well, sometimes certain opponents with high-quality decks cannot be beaten conventionally, and against these opponents its worthwhile to sacrifice some consistency for some power. When it's clear that the maindeck is not favored in the matchup, it's better to push the envelop by bringing in powerful cards to replace the weakest ones.
Going beyond the core colors may provide any number of things, typically removal spells, card advantage, or overpowered creatures. Splashing into a third color without proper fixing is going to degraded the manabase, but when it works out it will provide a more powerful deck better-equipped to deal with the problem at hand.
Compared to the other cases today, the power splash is the most difficult to properly pull of. A key factor in the power splash is the awareness of the opposing deck and knowing what it will take to beat it. The other key factor is knowledge of one's own deck, what possible power splash cards are, and how far the deck can and/or must be pushed.
The Silver Bullet
The silver bullet strategy will be familiar to anyone who has played constructed. Certain cards in the sideboard are no good for the maindeck, but will be extremely powerful in context.
Artifact and enchantment removal sticks out, as does specific color-hate cards. Counterspells are excellent options when the opponent has powerful bombs that won't be beaten otherwise.
The key point to make here is to always keep in mind what the sideboard has to offer and to re-evaluate after every game. Don't leave any quality players on the sidelines.
Sideboarding in Sealed Deck
The previously discussed techniques provide a very strong base for approaching a Sealed Deck tournament, and they cover the vast majority of sideboarding scenarios one will encounter.
I'm glad to answer any questions in the comments. What sideboarding techniques do you employ in Sealed Deck?