First off, as a speculative method of “solving” Sphinx’s Decree, running a deck with no spells when facing a white PW may be a way to avoid the risk of a freeze entirely.(Edit: This possibility seems to have already been addressed in the posts above since I began writing this post, so it admittedly no longer contains entirely original material)
Naturally, this hypothesis is difficult to verify conclusively, but based on limited testing in Story Mode and other players’ experiences posted on various external platforms, there’s a non-trivial possibility that the freeze conditions are twofold, and therefore are not necessarily (as seems to be widely believed) exclusively limited to factors outside of a player’s control should the opponent be using Sphinx’s Decree:
- One player casts (or otherwise controls on the board, e.g. via Whir of Invention or Refurbish) Sphinx’s Decree
- The other player has a spell in hand (this second aspect may be easy to overlook in many cases)
Given the frequency with which (2) occurs in a typical game and the difficulty of determining with certainty the exact contents of the AI’s hand at any given time, I don’t know how to reliably reproduce the situations needed to inarguably confirm or refute this idea, but I can confirm at the least that some additional condition is needed to induce a freeze beyond simply casting Sphinx’s Decree, as I was able to cast it in Story Mode after emptying the AI’s hand and continue the game normally for 2-3 turns before ultimately encountering a freeze later on during the AI’s turn (which occurred immediately after it drew a card with Decree still in play at that point). There may be other possibilities to consider as well, but as an operative assumption, exiling all spells from hand (and attempting to fill a hand with 6 creatures and supports) would help during any game against an opponent using Sphinx’s Decree if this hypothesis is correct, and using a deck without any spells would preclude the second condition from arising entirely in that case as well.
For those who wish to refrain from any speculation and would prefer deckbuilding solutions instead, here’s a list of potential ideas for reducing the odds of losing to Sphinx’s Decree without inordinately compromising a deck against other matchups. All of the examples range (subjectively) from strong cards and strategies to marginally playable ones (listed in no particular order), with varying levels of dependency on the surrounding deck archetype for optimal efficiency.
This is not an exhaustive list, and it’s entirely possible that other options may also prove effective for many players, but most of the omitted cards in these categories fall below the threshold of what I’d personally tend to consider playing as an answer to Decree even if I were certain to be facing a deck that included it in a given game, assuming the other 9 cards in the opposing deck weren’t also known in advance.
1. Discard or similar - Transgress the Mind, Whispers of Emrakul, Infinite Obliteration, Divest, Day’s Undoing, possibly Lost Legacy
2. “Counterspells” - Insidious Will, Pact of Negation
3. Mana denial - Sphinx’s Tutelage, Psychic Corrosion, Millstone, Overwhelming Splendor, Emrakul, the Promised End, Quarantine Field, Vryn Wingmare, Scatter to the Winds, Spell Swindle, Censor, Countervailing Winds
4. Hyperaggressive decks - There are various templates for this approach, but as a catch-all solution, often the best option for proactive defense is to abandon most attempts at reactive cards or a control strategy and instead aim to overload a deck with threats in order to win before the opponent has an opportunity to cast any problematic cards. Secondary objectives generally disincentivize this strategy as a default tactic, but playtesting may prove it to be the most efficient answer to a difficult problem in certain cases, and the very best decks (especially in Legacy) may incorporate extremely fast wins involving minimal interaction as an incidental reflection of their overall dominance rather than as a compromise made in lieu of access to better options.
Hopefully some of these possibilities will help as a temporary solution until the underlying problem can be addressed by the developers; in the meantime, good luck to anyone encountering Sphinx’s Decree in the wild, and sympathies to those who have been or may yet become unwitting victims of the freeze either when using or facing it during the normal course of play.