What's the Best First Guess in Cardle, the Hearthstone Version of Wordle?

Wordle, the word game craze that's sweeping the nation, has inspired a Hearthstone themed imitator, Cardle. Not sure what either of those things are? Here's a helpful primer!

In this article, we're going to be attempting to find the best first guess for Cardle, because nothing makes a game more fun than someone using math in an attempt to prove an optimal path when no one asked them to.

N.B.: For the sake of clarity, we'll be assuming throughout the article that each guess we make returns six red boxes, or what we're going to call "completely wrong."

The Problem with Guessing

The point of Cardle is to guess a Hearthstone minion within seven tries. For the sake of brevity (and our own sanity), we're sticking to the Standard setting of Cardle because that's what the game is set to when you first open the webpage.

We don't know if you know this, but Standard has a lot of minions (726, to be exact)! How in the heck are we supposed to guess one minion out of over 700 possible answers? It's all fun and games if we get Murloc Tinyfin on the first guess, but I think we all know that's highly unlikely (0.13%).

Cardle gives us some help in the form of six boxes of information, as well as directional eliminator arrows, that will let us narrow down our guesses: The minion's Expansion, Class, Rarity, Cost, Health, and Attack. That's a lot of information, and it'll be very helpful if you know how to use it. For instance, if we type in Murloc Tinyfin, and get six red squares, then we know that the minion is not Neutral or Common (or Murloc Tinyfin). With that one guess, we have eliminated 284 Neutral minions, as well as 157 (non-Neutral) Common Minions. We've also eliminated another 35 (non-Neutral, non-Common) minions that belong to the Core set. With one (fairly awful) guess, we've narrowed our pool of possible minions down to 250 (or 34%). And that isn't counting any other minions with 1 (or 0) Attack or 1 Health which have also been eliminated from contention.

Let's Solve Cardle

So clearly our best strategy is to guess minions that narrow down the potential options as much as possible. We won't bore you with too many specifics (unless that's what you want; comment below!), but by crunching the numbers on the types of minions in Standard it becomes apparent that the "Class" with the most minions is Neutral (284 minions--next most is Demon Hunter, with 58) and the Rarity with the most minions is Common (318 minions). That's easy, lots of minions are Neutral and Common. So we can just guess Chillwind Yeti and nobody has to do any more math.

But wait, there's more (math, that is)! Because we're looking for a minion whose traits eliminate as many other minions as possible, it would profit us to take advantage of Cost, Attack, and Health, and that means breaking the minion pool down even further. Thanks to outofcards' card search database, we can figure out which of each of those traits is shared by the most Standard-legal minions. For instance, we can find that 172 minions Cost 3, 196 minions have 3 Attack, and 153 minions have 3 Health. So is the answer that we guess Earthen Ring Farseer?

Not so fast! Just because a minion has Cost and stats that are the most common doesn't mean it's going to eliminate the most other minions from our pool of potential guesses. You see, while 3 is the most common number among minions for any trait, it isn't that huge of a share. For instance, there are only 11 more minions with 3 Health (153) than minions with 4 (142).

Beyond just guessing numbers that a lot of minions have in common with a variety of other minions, we also need to take into account the eliminator arrows. The extra information we get from the arrows can tell us that the minion in question has a lower Cost or a higher Health, thus eliminating more minions. And because Cost, Attack, and Health don't exist apart from each other, we can use minions with traits whose numbers are near, but necessarily all equal to, 3 to create a pincer that will eliminate much more minions that just guessing all 3s.

In the next section, we'll discuss what other kinds of clues we can get from eliminator arrows while looking at the last two pieces of information that can let us make a better second guess.

Follow the Arrows

The arrows do more than just tell us numbers. Among the six boxes in a typical game of Cardle, five of them use eliminator arrows, and now it's time to examine the last two: Expansion and Rarity.

While the arrows for the numbered traits are self-explanatory, these two traits are a bit more tricky. The arrow on Expansion is referring to the chronological release of each expansion in Standard, EXCEPT that Cardle treats the Core set as the first set (i.e.--a red Core box always has its arrow pointing up). That means if we guess a minion from Madness at the Darkmoon Faire, we will only have to worry about three expansions no matter which way the arrow points (Down: Core set, Ashes, Scholomance; Up: Barrens, Stormwind, Alterac). That effectively cuts the field of minions in half.

Now, let's talk about Rarity. Although Common contains the most cards, it is also the lowest Rarity--that means any time we get a red Common box the arrow will always point up, narrowing our guesses to 408 minions. That's not very helpful, is it? If, instead, we guess a Rare minion, we can gain so much more information: a red arrow pointing down means we have 318 minions (Common) to guess from, while a red arrow pointing up leaves us with 246 minions (Legendary and Epic).

The Conclusion

So what have we learned? Well, we learned how to turn discrete information to our advantage by making use of Cardle's clue system to eliminate as many minions as possible with just one guess. Thanks to math (thanks, math!), we know (in theory) what our ideal minion to guess looks like that will give ourselves a workable strategy for narrowing it down to the minion in question. And, thanks to arrows that point towards the solution, we can guess with confidence and use that information to win Cardle (what do you mean, "You don't win Cardle"?).

So what is the best minion to guess? First, I'd like to welcome everyone who scrolled past the miles of text to get right to the answer. Thanks for joining us! As established, we want to guess a minion that is Neutral and Rare because a wrong guess eliminates the most possibilities, as well as one from Madness at the Darkmoon Faire because it resides directly in the middle of legal expansions. Beyond that, our last three traits to calibrate are Cost, Attack, and Health, and we want a minion whose trait numbers create a "pincer" that narrows down the options while still remaining in the "hot range" of numbers from 2 to 5. Our conclusion is that the best minion to guess first in Cardle is: Derailed Coaster.

This is what peak performance looks like.

Derailed Coaster checks all of our boxes: it's Neutral (eliminates 284 minions), it's Rare (eliminating an additional 277 or 285 minions depending on arrow direction), and its Cost, Attack, and Health are all fairly common numbers that work in tandem to reduce the number of possible minions further.

For similar reasons (and because it feels cheap to give only one answer after so much work), we think that K'thir Ritualist is also a good first guess.

While it's not perfect (and perhaps a little anticlimactic for the amount of work we did to get here), we believe that these two minions will give you the most actionable information from a completely wrong first guess thanks to their position within the five traits that use eliminator arrows.

Are you enjoying Cardle? Have you got your own fool-proof system that blows ours out of the water? Share it in the comments!