Since its unban in February, Jace, the Mind Sculptor has been making a large impact on Modern. It found a natural home in W/U Control, which has been dominating the format since. At the last Modern Grand Prix, W/U Control was the most popular archetype in Day 2 and in the Top 8, and its success was partly due to the powerful 4-mana planeswalker.

All four abilities are good, but today I want to focus on the first. When you +2 to fateseal the top card of your opponent’s deck, the standard line of play is to put the card on the bottom of their library if it’s a powerful one and to leave it on top otherwise. This way, you get to control your opponent’s draw steps.

There is little your opponent can do about it, unless they control a fetchland. If Jace’s fateseal leaves a card on top of their library, which seemingly indicates it’s a superfluous land or a useless spell, then they can crack their fetchland to shuffle their library and get a fresh draw step. For this reason, it can be valuable to leave fetches uncracked against Jace decks.

I watch a fair bit of coverage, and this year I saw a face-off between Jace and fetchlands twice, with different outcomes.

In Round 13 of Pro Tour 25th Anniversary, Mattia Rizzi used his Jace to fateseal Ben Hull, leaving the card on top.

“You know you’re in rough shape when your opponent starts Jacing and plusing, targeting you,” Paul Cheon commented. “Oh yeah, especially when they let you keep the card,” Marshall Sutcliffe replied.

With the expectation that Jace had left a useless card on top of his deck, Ben Hull used his Bloodstained Mire to shuffle his library. As the commentators explained, fetching makes sense when you need to find some threats soon. But it’s more complicated than that.

In Round 12 of Grand Prix Hartford 2018, Julian De Los Santos used his Jace to fateseal Colton Abrams, leaving the card on top.

Yet despite controlling a fetchland, Colton Abrams chose not to shuffle his library. Twitch chat was surprised, and several viewers were wondering, “why not fetch when Jace left the card on top?”

Well, there’s actually a possible reason for that!

The Mind Games

If we take the perspective of the Jace player, and if we expect our opponent to always crack their fetchland after a fateseal leaves a card on top (which, in my experience, is what most players tend to do), then we should snap top every time, no matter what we see.

This way, our opponent is guaranteed to lose their fetchland, which means that the next fateseal activation is more potent. Every fetchland they have is a chance to break the fateseal-lock, so you gain an edge if you deprive them of that resource.

But the leveling continues. If our opponent expects us to leave every card on top, then they shouldn’t crack their fetch, at least not immediately. This is exactly what Colton Abrams may have been thinking. It requires a strong belief that your opponent is trying to next-level you by leaving a powerful spell on top, but it’s a possible answer to the question from Twitch chat.

But how often should the Jace player take this risky route? And how often should you go deep by not fetching? All of this depends on the context. Since neither player knows the other player’s strategy, it turns into a guessing game, but I can analyze a specific example as an illustration.

An Example: W/U Control vs. Burn

Suppose that we have a match between W/U Control and Burn. The Burn player has no cards in hand and no non-land permanents, but they do control a Bloodstained Mire. Also, they have gotten the W/U Control player down to 3 life, in range of a Lightning Bolt or Lava Spike.

The W/U Control player starts their turn with Jace at 8 loyalty counters. Hence, the Burn player has two draw steps to find a lethal burn spell, or they’ll die to the ultimate. For the sake of simplicity, suppose that the Burn player’s library consists of 40% lethal burn spells and 60% useless cards. (The W/U Control player holds Path to Exile for any creature, and the number of fetchlands remaining in the Burn player’s library is negligible. Also, for explanatory ease, I’ll assume that their library is infinitely large.)

Given this situation, both players have to formulate a strategy. For the Jace player, this comes down to deciding whether or not to bottom a burn spell if they see one on top with the first fateseal activation, i.e., when Jace ticks up to 10. (A useless card should always be left on top. And if Jace gets to tick up to 12, then for the second fateseal activation they will always put a burn spell on the bottom, regardless of whether there’s a fetchland or not.)

For the Burn player, they have to decide what to do if the first fateseal leaves the card on top: To fetch or not to fetch? (If the first fateseal puts the card to the bottom, then there’s no point in shuffling. And for the second fateseal activation, you’ll shuffle your library regardless, as there’s no point in cleverly trying to hold on to your fetchland for another turn if the entire game will be decided by your next draw step.)

Putting it all together, we can represent the situation as follows. The rows represent the Burn player’s strategy when the first fateseal leaves a card on top. The columns represent the Jace player’s strategy with the first fateseal. The numbers for every strategy profile are the corresponding probabilities of winning the game from our starting position.

Leave burn spell on top Put burn spell on bottom
Fetch (49.6% Burn win, 50.4% Jace win) (55.36% Burn win, 44.64% Jace win)
Don’t fetch (64.0% Burn win, 36.0% Jace win) (49.6% Burn win, 50.4% Jace win)

To explain how these numbers arose, consider for instance what would happen if the Jace player plans to leave a burn spell on top while the Burn player plans not to fetch after the first fateseal. Since the probability of seeing a lethal burn spell on top is 40%, the probability of drawing a lethal burn spell in the first draw step under these strategies is also 40%. In the remaining 60%, the second fateseal will be effectively countered by the lingering fetchland, giving another 40% of drawing a lethal burn spell. Since 0.4 + 0.6 * 0.4 = 0.64 and since 1 – 0.64 = 0.36, you get the numbers in the table. The numbers for the other strategy profiles are calculated in a similar way.

Since there is no strategy that dominates all others for any player, your best strategy depends on your opponent’s strategy. But there is a mixed equilibrium: If the Burn player fetches after a fateseal-top with probability 5/7 and the Jace player pushes a potential burn spell to the bottom with probability 5/7, then no player has an incentive to deviate from that strategy. You could say that their strategies are unexploitable, and if both players mix their plays in this way, then they are in an equilibrium. If you’re curious, the Burn player is 53.7% to win the game in this equilibrium.

Either way, this analysis shows that occasionally bluffing (by leaving a lethal burn spell on top) and occasionally calling (by choosing not to fetch) is a good way to approach these scenarios.

Conclusion

When you +2 Jace to fateseal your opponent while they control a fetchland, you should sometimes leave every card on top, even if it’s a lethal burn spell. The reason for this is that if you expect your opponent to fetch anyway, you get to deprive them of a resource that they could have used to break out of the fateseal-lock later.

Conversely, if your opponent leaves your card on top with Jace, then sometimes you should not crack your fetchland at all. They might be trying to next-level you, and there might still be a lethal burn spell on top. But no matter what strategy you pick, just being aware of these mind games may be helpful in your next Modern tournament.