Whenever we playtest for an upcoming tournament, we always remember to do both mainboard and sideboarded games. Typically, we want to test more games with sideboards than mainboards. This is because in BO3 (best-of-3) matches, you play exactly one game with mainboards and at most two games with sideboards. Thus, if your win rate versus a deck improves considerably post-board, then you should not consider that deck a bad matchup for purposes of deck selection. Making sure that you are not on the wrong side of the meta is critical to deck selection. With Magic: Arena, WotC has introduced a new dimension of competitive magic: BO1 (best-of-1) games. Arena’s rank ladder currently applies only to BO1 matches in both limited and constructed. In this article, I focus on the latter and examine how BO1 changes the dynamics of deck construction and selection. I also analyze the efficacy of different decks in the current BO3 meta in the BO1 setting.

Throwing caution to the wind

In a BO1 setting, you only get to face each opponent once per match. Without sideboarded games, this means that decks that are very strong game 1 despite being easy to counter with the sideboard are good deck choices. This makes aggressive strategies more appealing than either midrange or control strategies. Aggressive strategies are typically the best that they can be in game 1, with almost every card in the deck directly contributing to its win condition. For example, a Mono-Red deck typically has only 2 Lava Coils as cards that do not directly help them win. The rest of the deck are creatures, direct damage spells, and Experimental Frenzy (itself a win condition). On the other hand, both midrange and control strategies need to balance control elements with win conditions. If they include more control elements, they stand a better chance of winning against some aggro decks but significantly worsen their matchups versus other decks. This is a much smaller issue in BO3 matches since the 15-card sideboard allows both midrange and control decks to adjust their strategies so that they can be much more powerful post-board versus their current opponent. On the other hand, aggro decks typically have sideboards that water down their aggressiveness in exchange for having a way to counteract the cards that their opponents will be bringing in against them.

The same analysis is applicable not just for aggro decks but for linear decks in general. Some linear decks are too slow to be considered aggro, but just the same throw caution to the wind game 1 by loading up on cards that help accomplish their end game with little consideration as to what cards their opponents would have. Selesnya Tokens and Merfolk are good examples of these decks. Another class of decks that work well in the BO1 meta are decks that have a lot of interaction but have these interwoven well with their game plan. For example, Izzet Drakes has cheap removal spells but these help in getting their Arclight Phoenixes out of the yard. Mono Blue Tempo has a lot of counterspells which are used both to protect their creatures and to counter opponents' game-winning spells.

So you shouldn’t play midrange/control?

In the great rock-paper-scissors of MTG, aggro-beats-control-beats-midrange-beats-aggro. If aggro/linear decks are indeed favored in the BO1 setting, does it mean you should not play midrange/control? Here is where it gets somewhat tricky. In BO3 magic, the meta tends to stabilize after some time, leaving only decks that are competitive both in both pre and post-boarded games. Some decks that are good in game 1 versus multiple decks get pushed out because their game 1 advantage is easily mitigated in the sideboard. Examples of these are Merfolk, Mono Green Stompy, and Elf Ball.

In BO1, if you know that over 50% of players are using aggro decks, then playing a control deck that is tuned to beat aggro can lead to favorable outcomes. Such decks differ considerably from control decks that strike a balance between combating aggro and other decks, and differ also from control decks that are turned specifically to winning the control mirror. As such, these decks which are essentially different configurations of the same control deck in the same colors need to be treated differently in terms of evaluating their winnability, which leads to a much more diverse meta. Such a meta may not even stabilize since any stabilization, once it becomes apparent to players, can be taken advantage of. This means that an important aspect of playing midrange/control decks is still having a sideboard of sorts. That is, you should be able to tweak your deck to different configurations depending on what seems to be the existing meta at a given time. For example, if you feel like you are facing one White Weenie/Boros aggro deck after the next in ranked matches, then it may be a good idea to include that third copy of Ritual of Soot and those two copies of Golden Demise on your next match. Catching the meta this way is likely quite difficult though, so in my book going with a linear strategy is still more appealing. As long as a majority of the playerbase is not gunning for Mono U Tempo, I should be able to climb steadily up the ranks (for what little that’s worth right now).