William James Checks in the Dark

"What difference would it practically make to anyone if this notion rather than that notion were true? If no practical difference whatever can be traced, then the alternatives mean practically the same thing, and all dispute is idle. Whenever a dispute is serious, we ought to be able to show some practical difference that must follow from one side or the other’s being right. ...

It is astonishing to see how many philosophical disputes collapse into insignificance the moment you subject them to this simple test of tracing a concrete consequence. There can be no difference anywhere that doesn't make a difference elsewhere—no difference in abstract truth that doesn’t express itself in a difference in concrete fact and in conduct consequent upon that fact, imposed on somebody, somehow, somewhere and somewhen."

~William James, "Lecture II: What Pragmatism Means", in Pragmatism: A New Name for Some Old Ways of Thinking (1907)

As a philosophy major, I was always strongly drawn to pragmatism because of its emphasis on linguistic clarity and logical consequences. The core principle of pragmatism, stated by philosopher William James above, can be paraphrased like this:  A difference, to be a difference, must make a difference.

I was reminded of this core principle of pragmatism this past week when an interesting debate erupted on the All Vegas Poker discussion forums over the relative merits of a common poker maneuver—checking in the dark. [FN1]  For those unfamiliar with the term, checking in the dark (or "checking dark") simply means that the player first to act on a subsequent betting round exercises his betting option by checking before the next board card(s) are put out by the dealer, rather than waiting to check until after the player is able to see the board card(s). Checking in the dark has been popularized by the televised antics of players like Phil Hellmuth (who at times seems almost addicted to the play). But I have to wonder, have any of the players who routinely employ the maneuver actually analyzed whether checking dark is a smart play?

Applying the principles of pragmatism—or Sklansky's Fundamental Theorem of Poker, if you prefer—if checking dark is a good maneuver, it will give a poker player some advantage over the player who employs the more traditional check. Now the player checking dark invariably will be playing the hand out of position, placing them at a distinct disadvantage. A player first to act will typically end up checking a rather high percentage of the time, either out of weakness from missing the board, or out of strength when disguising a hand that strongly connected with the board. However, a player first to act will find that leading out with a bet is advantageous in a variety of situations, including:

• Flopping two pair or a set on a draw heavy board.
• Betting a middle pair or bluffing on a dry, junky board.
• Blocking a bet the first to act player cannot call.
• Putting the opponent to the test on a scary board (e.g., a flop with an Ace, or a turn or river card that completes an obvious draw).

Now this isn't to say that a player will lead out with a bet on all of these boards on all occasions. The point is that checking dark deprives a player of the option of making these plays. Clearly giving up the option to lead out with a bet on hands where doing so is the correct play is -EV. So, if it has any value, the dark check must be a sufficiently powerful, profitable maneuver to overcome the disadvantage of giving up the ability to bet boards where doing so is the correct play.

Given the obvious disadvantages caused by checking dark, what are the possible advantages of checking dark? In all of the discussions I've heard and read on the subject, three reasons for checking dark come up the most frequently: a) checking dark reverses the position of the players when heads up, b) checking dark disguises the strength of a player's hand, and c) checking dark prevents a player from giving out information on the strength of his hand. On closer examination, all three justifications are spurious.

With respect to "reversing position" of the players, checking dark simply does not reverse the positions of the players, either actually or effectively. The player checking dark still acts first, he simply exercises that option prior to the next board card being put out. Here we return to the principles of pragmatism—what is the difference between checking dark and checking normally? In terms of position, there is no difference. If the player first to act checks, the other player can bet or check behind as usual, and it doesn't matter if the first check was dark or not. If the first player to act in a heads up situation checks dark, and the other player checks behind, the dark-checking player does not miraculously gain the ability to act, as they would if they were in position. So, as there is no difference in action whether the opening check is dark or normal, there is no positional advantage gained by checking dark.

So what about the claim that checking dark disguises the strength of a player's hand? This argument essentially states that because the player first to act usually checks, a dark check prevents the other player from knowing whether a flop (or turn or river) was helpful to the dark-checking player. Let's assume a player acting first would normally check 70% of the time out of weakness, check 10% of the time out of disguised strength, bet 10% of the time out of strength, and bet 10% of the time as a bluff. A dark check has no effect on the check out of weakness play or the check out of strength play, as a dark check and a regular check each look the same to a rational opponent. But a dark check deprives the player of the ability both to bet strong hands and to bluff. So, a dark check gives no advantage to hands to a player who wants to check, but hurts a player by depriving him of the chance to bet certain hands. Assuming a player balances his donk bets between betting strong hands and bluffs, a dark check that takes both plays out of the equation simply does nothing to disguise the player's hand that cannot be accomplished by normal, solid play. But if a player is stupid enough only to bet his strong hands out of position, then a dark check might in fact be a decent play, though the move is likely more than offset by those hands where a donk bet is the correct play and the dark check leads to a check behind. Of course, such a player has a whole other kettle of fish issues to worry about.

Finally, let's look at the claim that a dark check prevents a player from giving out information as to the strength of his hand. We just looked at situations where a player checks his weak hands and bets his strong hands, but what about the more sophisticated player whose betting patterns do not reveal his hand strength? In these situations, advocates of checking dark maintain that the maneuver prevents the player from revealing whether they are strong or weak by taking out of consideration elements such as facial reactions and timing of response. Of course, this argument assumes the dark-checking player never looks at the board before their opponent acts. But if a player is bad enough to give off reliable physical tells about the strength of his hand, then checking dark is almost certainly the least of his worries—any decent player will simply eat the dark checker alive based on his physical tells which he will eventually have to give off when he inevitably looks at the board.

In summary, then, for most players checking dark is almost certainly a -EV maneuver compared to simply playing a hand normally and checking when appropriate. For a small handful of players—multiple WSOP bracelet winners and tell-spewing donkeys—checking dark might occasionally be a decent play. In other words, although plenty of players have convinced themselves they are making a sophisticated play by checking dark, their thought process is flawed. Good players don't check dark. [FN2]

"A great many people think they are thinking when they are merely rearranging their prejudices."

~William James

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[FN1]  The debate was reminiscent of a similar debate on the AVP forums a few years back. Also, as is usually the case, Poker Grump has already weighed in on the debate with this thoughtful post.

[FN2]  Of course, players like Phil Hellmuth are sufficiently better than most of their opponents that they can overcome the -EV of using the dark check. That doesn't mean that checking dark is a good play on its own merits.