Often in Magic, what matters in a given matchup is common knowledge. The Jeskai Black mirror came down to card advantage. W/G Tokens beats B/G Company with Ormendahl, Profane Prince and Archangel Avacyn; nothing else really matters. Heuristics like these are constantly bandied about between Magic players at tournaments and in playtesting, and while soundbites like these can never be wholly accurate, they're often close enough.
Figuring out the axis that each matchup revolves around has never been easier — but everyone has access to the same information.
Sometimes your best bet lies in making the matchup revolve around a new axis.
Let's examine the Jeskai Black mirror of last Standard.
There was a time in the last format when it felt like we as a community discovered Painful Truths out of thin air. The card went from zero to hero overnight, if you define hero as a common four-of in multiple top decks. Jeskai Black mirrors during this time period were all about the Painful Truths battle. The weapons of this battle were as follows: 3-4 copies of Painful Truths you wanted to resolve, 1-3 copies of Duress with which to take opposing Painful Truths, and 0-2 copies of Negate with which to counter opposing Painful Truths. Realistically, these were the only cards that mattered in the important fight. The problem was that being more prepared for the Painful Truths battle only improved the odds of winning the mirror by about 5%.
Devoting substantial sideboard space to a 5% edge to a single battle in a single matchup is a hard sell. It's important to note that winning the Painful Truths battle didn't guarantee victory in the game. Generally, the person who has more cards wins the mirror, which is why Painful Truths came to be so important. But if optimizing the Painful Truths game doesn't pay off, the play is to find a new plan.
The key to the new plan ended up being the life loss off of Painful Truths. The three-point life loss from Painful Truths combined with the multitude of fetchland activations meant that Jeskai Black typically did a sizeable amount of damage to itself in the course of a single game. I started forfeiting the Painful Truths battle to my opponent, boarding into Mantis Rider to punish them for using life so freely as a resource. Combined with using the cards I already had in new ways, for instance being more willing to use Kolaghan's Command to damage my opponent, Mantis Rider was an effective trump to the Painful Truths fight.
The plan here was to gain an advantage in the actual game by ceding my chance to gain an edge in the Painful Truths subgame. Note that I just forfeited my edge in the subgame, not all my winning chances — as previously stated, that battle never felt like it could be swung past 55-45. So 45% of the time I still resolved more Painful Truths than my opponents, despite not even trying to compete on this axis. This is the concept of Diminishing Returns at its finest. You can overload on ways to stop your opponent's copies of Painful Truths while resolving your own, but each successive card you play in this vein does less and less to move the percentages in your favor. The first Duress you play gives you maybe 2%. The next, 1%. So on and so forth, with most of the cards you play to this effect having very little impact on the percentages. The reason is that the bulk of the battle, the Painful Truths themselves, are already maindeck on both sides, and all the Duresses and Negates in the world can only shift things a little bit. On the other hand, the first Mantis Rider you play out of the board gives you a solid 15-20% edge in the damage battle, as it's the first card either player is playing for that effect. Finding an unopposed axis to battle on that can affect the outcome of the game is a great way to make your sideboard slots more impactful.
How can the idea of 'giving up' on what conventional wisdom says is important in a matchup help in Shadows over Innistrad Standard? Let's start with the W/G tokens mirror. One of the important battles in this matchup is for control of the board, and with it, the ability to protect Planeswalkers while putting relevant pressure on opposing Planeswalkers.
Lambholt Pacifist has become commonplace as a way to put a cheap but sizeable body on the battlefield that threatens to assasinate a near isolated Planeswalker with the help of Dromoka's Command. In this Planeswalker battle, the main tools are two-drop creatures like Lambholt Pacifist and Sylvan Advocate, removal spells like Dromoka's Command and Declaration in Stone, and the Planeswalkers themselves in Gideon, Ally of Zendikar and Nissa, Voice of Zendikar. Gideon, Ally of Zendikar in particular is pivotal, as he is both something you need to defend and something that will add significant pressure to opposing Planeswalkers.
Diminishing returns are going to kick in pretty quickly. The seventh two drop or removal spell yields only a minor edge against an opponent with six, and everyone is playing all eight Planeswalkers already. Instead, I've been opting out of ensuring that I come out ahead on the ground and taking to the skies with Gryff's Boon.
In the stock W/G lists, the air battle doesn't begin until Archangel Avacyn and Ormendahl, Profane Prince become relevant in the midgame. Boarding in 2-3 copies of Gryff's Boon allows me to Assassinate a Nissa, Voice of Zendikar or a Gideon, Ally of Zendikar much earlier than that, effectively winning the Planeswalker battle on another axis.
The first Gryff's Boon in the sideboard is so much more impactful to the game than a seventh removal spell, as early flying is a perfect example of the kind of unopposed yet important axis. Deciding to use limited sideboard slots on Gryff's Boons instead of more Declaration in Stones doesn't mean the ground board control battle is automatically lost. To the contrary, opposing Declaration in Stones are low-impact and will only swing the ground battle in their favor a small percent of the time. Even with Gryff's Boon, you will still win on the ground almost half the time.
Let's consider the breakout of Four-Color Company, an evolution of B/G Company. What prompted the massive change? It's a matter of axes, but before discussing that it's important to understand the nature of the W/G Tokens / W/G Tokens matchup. On its face, this matchup is a massive stall. Both sides clog the board up with piddly creatures and neither can get in meaningful attacks until late in the game. If this stalled game continues uninterrupted, W/G will eventually win with its multiple Planeswalker anthem effects giving it a formidable board advantage. But the matchup rarely reaches this point, as before this can happen, B/G has more than enough time to assemble a potent Zulaport Cutthroat / Nantuko Husk board state or a lethal Ormendahl, Profane Prince attack. W/G has two trumps of its own that it plays to: flipping Archangel Avacyn, generally with either the Hangarback Walker trick or a Dromoka's Command fight, or summoning its own Ormendahl, Profane Prince. This is the axis the matchup hinges on: can W/G get to Avacyn the Purifier or Ormendahl, Profane Prince in time, or not?
B/G can't really interact with W/G's race to these cards. It can try using Ultimate Price to interact with Archangel Avacyn before she flips, but that does nothing to stop Ormendahl, Profane Prince. B/G's best bet on this axis is to concentrate on its own speed, denying W/G the time it needs to find its important cards. At least, that was its best bet until Four-Color Company hit the scene.
The dynamic at play in the Four-Color Company / W/G Tokens matchup is nearly identical to the B/G matchup: the board stalls, Four-Color will assemble its combo and win unless W/G hits Archangel Avacyn or Ormendahl, Profane Prince first. But now the Rites deck can interact with these cards! Eldrazi Displacer will never let Archangel Avacyn flip and Reflector Mage can deal with Ormendahl, Profane Prince. Now Company can interact with W/G but W/G still can't interact with the Company deck. The important axis has changed from a race of who can land their important cards first to Company halting W/Gs plan while continuing to progress to its game winning board state. By opting out of the race, Four-Color Company shifts the matchup to revolving around an axis much more in its favor.
Thanks for reading,