Sideboarding, a source of frustration for some, is a source of opportunity for the savvy player. Sideboards allow players to adapt their strategies in any number of ways to next-level their opponent. A very recent example is from Tomoharu Saito’s UW Azorius Control deck in Standard. His maindeck is a creatureless UW control strategy. The stock Standard UW control deck plays no creature, so opponents expect Saito to have no creatures. Saito one-upped them by bringing in Soldier of the Pantheon and Archangel of Thune in game 2 , and opponents were caught off guard. The story goes that Saito would bring in this package against every single opponent, and he used the strategy to reach the elimination rounds of two PTQ in a row and put himself within a game of the invitation. This strategy is employed time and time again. Always be aware of everything the opponent is capable of.
[cardimage cardname='Archangel of Thune']
Keep in mind that sideboarding strategy needs to take into account what the opponent is going to sideboard. You are not sideboarding against their game one deck, but against their post-sideboard configuration. This creates a world of meta-sideboarding, so keeping up to date on what popular decks are sideboarding is a necessity. Some online research into popular decklists provides total awareness of what opponents are likely to have access to in games 2 and 3. Sideboards are typically used to combat the common decks in a tournament metagame. Certain matchups pose more problems than others, so sideboards are tailored specifically to beat the most difficult opponents.
Anger of the Gods has become the best sweeper in the post-ban Modern format. This was formerly Pyroclasm, but the move away from the format defining, two-toughness Deathrite Shaman towards the three-toughness Wild Nacatl has raised the critical damage threshold accordingly. Anger of the Gods is a sweeper for three that also exiles creatures, meaning it hoses persist creatures and Voice of Resurgence. Anger of the Gods is used in the sideboards of many top decks, including UWR Control, Jund, and Splinter Twin combo.
UWR Control won the Pro Tour, and it relies on counterspells and targeted removal to deal with creatures. The deck has no good answer to Thrun, the Last Troll, so it puts the opponent on a very quick clock. Be careful to play around Porphyry Nodes, a possible sleeper hit for the UWR control deck this weekend. Thrun’s 4 toughness also insultates him from the now-popular Anger of the Gods, so very few of the popular removal spells in the Modern format can handle this threat.
Modern is driven by its fetchland-shockland manabase, and Blood Moon hoses it completely. It also turns off the huge number of utility lands in the format like Desolate Lighthouse and Celestial Colonnade. Nearly every opponent is playing multiple colors, and many of them are extremely susceptible to Blood Moon. It is a great tool in the arsenal for some, and a dangerous threat to others. Blood Moon is most often seen in the sideboards of UR combo decks like Splinter Twin and Storm, but it also sees play in some UR Control decks and the occasional Affinity deck.
Another card that attacks the manabase of Modern decks is Fulminator Mage. This card is in nearly every BG Rock and Jund sideboard. It functions as specific hate against Urza Tron and Scapeshift, but is used broadly against any mana-hungry deck. Fulminator Mage is often used in mirror matches, against UWR Control, and against all combo decks.
Modern is filled with powerful two-drop creatures, most importantly Tarmogoyf, Dark Confidant, Voice of Resurgence, and Spellskite. Threads of Disloyalty is a full-fledged Control Magic against these creatures, a two-for-one in card advantage and a tempo-positive play. In a pinch Threads of Disloyalty can disarm cards like Wild Nacatl and Kird Ape. Threads of Disloyalty is seen from the sideboards of Splinter Twin combo and UWR Control, but I would expect it from any blue deck focused on board presence.
One final tip: When playing paper Magic for high-stakes against astute opponents, shuffle in 15 cards every time! The opponent will see you take fifteen cards out, but they will have no idea how many cards you actually changed. Best to keep them guessing. Have fun this weekend!