How to Sideboard in MTG: Win Games Two and Three

A sideboard is a set of up to 15 additional cards you bring alongside your 60-card main deck in constructed formats. You cannot use the sideboard during the first game of a match, but between games you may swap any number of cards one-for-one between your main deck and sideboard, as long as your deck returns to its minimum size. The sideboard lets you tune your deck against the specific opponent you are facing.

Matches are usually best-of-three, so after losing or winning game one you have learned what your opponent is doing. Sideboarding is your chance to replace cards that are weak in this matchup with cards that are strong against it. A well-built sideboard can flip an unfavorable matchup, which is why competitive players spend as much time on their 15 sideboard cards as on parts of the main deck.

After game one, identify which of your main-deck cards are underperforming against this opponent. Removal that targets creatures is dead against a control deck with few creatures, and a slow value card is useless against fast aggro. Take those weak cards out and bring in sideboard cards that directly attack the opponent's plan, swapping the same number out as you bring in so your deck stays legal.

A good rule is to make focused, meaningful swaps rather than overhauling your whole deck; bringing in too many cards can dilute your core strategy and ruin your curve. Typically you change three to six cards. The player who lost the previous game decides whether to play or draw first in the next, so factor that tempo advantage into which cards you want. Remember to return your deck to its main configuration before the next match begins.

Most sideboards are built around a few recurring categories. Extra removal and sweepers come in against creature-heavy aggro and go-wide token decks. Graveyard hate answers reanimator and recursion strategies. Artifact and enchantment removal handles decks built around those permanents, and cards that gain life or add blockers shore up fast aggressive matchups. Anti-control tools like extra threats, hand disruption, or cards that are hard to counter help in grindy control mirrors.

Build your sideboard by predicting the decks you expect to face and dedicating a few slots to each problem. Flexible cards that answer multiple threats are valuable because sideboard space is tight at only 15 cards. Practice your sideboard plans before a tournament so you know exactly what comes in and out against each archetype; sideboarding well under time pressure is a skill that wins matches just as much as the cards themselves.