Evaluating Backdoor Draws in No-Limit Hold'em

Poker Strategy / Short-Stacked Shamus / 29 September 2011 / Leave a Comment

Running hearts fill a backdoor flush

Backdoor draws do have value and should be considered when making flop decisions. In fact, better hold’em players routinely account for the possibility of hitting a backdoor draw when evaluating how to play the flop.

Last night saw the final day of Major League Baseball's regular season punctuated by some thrilling conclusions to multiple games. With playoff spots in the balance, no less than three different games had come down to the losing team's final at-bats when unexpected reversals of fortune occurred.

In all three cases -- including a couple in which the winning team was just one out away from winning -- the losing teams scored runs to extend the games, then eventually win. It was like watching three straight poker hands play out in which improbable backdoor draws came in, with the player who was comfortably ahead surprisingly seeing the pot go the other way.

While we're all used to suckouts in poker -- having endured them by others, or benefitted from them ourselves -- we generally do not consciously seek out spots to "get it in bad." Indeed, better players are more often on the losing end of such scenarios when they occur, having successfully outplayed their opponents into committing chips with the odds against them.

Still, backdoor draws do have value and should be considered when making flop decisions. In fact, better hold'em players routinely account for the possibility of hitting a backdoor draw when evaluating how to play the flop.

The Extra "Out"

To explore an example, consider for a moment the value of flopping a backdoor flush draw in no-limit hold'em. Just in terms of percentages, what is it really worth to flop three to a flush?

Let's say you raise before the flop from late position with Ah-Kh and get a couple of callers in the blinds. The flop comes 10c-7h-2d. The small blind bets and the big blind calls.

As you try to decide whether or not to stick with the hand, of what value is that single heart on the board? Well, setting aside particulars regarding your opponents' styles and/or possible holdings, the presence of a backdoor flush draw is usually worth a few percentage points to you here in terms of your chances of ending with the best hand -- a small, but potentially meaningful difference.

In order to illustrate, we'll give your opponents a couple of hands with which they might have called your raise -- say Qs-10s and 4d-4s -- and run the numbers.

Odds calculators differ, but most suggest Qs-10s (with a pair of tens) is a little more than a 64% favorite here, the guy with pocket fours is way behind at around 8%, and you are just over 27% to win with your two overcards.

Now let's take that heart away and make the flop 10c-7c-2d. Now Mr. Jack-Ten's chances improve to close to 68%, yours decline to just under 23%, and the fellow with pocket fours remains well behind at a bit more than 9%.

On the surface, having a ~4% better chance at drawing out might seem like a negligible difference. Actually, it's just about the same as the difference between flopping a flush draw (where you're about 36% to hit) and an open-ended straight draw (about 32%). Knowing this -- or at least being vaguely aware that flush draws hit more often than do straight draws -- a lot of players are more willing to draw to a flush than a straight.

With a flush draw you are looking for 9 outs and with an open-ender 8 outs, so really what we're talking about here is a difference that equates to having about one additional out. Knowing that, if you're sitting in this spot thinking the three aces and three kings represent outs to you, you might go ahead and add one more "out" to that total if you additionally have a backdoor flush draw.

Nothing Funner Than Runner-Runner

The question remains, however -- is having that extra "out" really important enough to affect our decision-making here? To answer that, there's one other factor you might want to keep in mind when evaluating the worth of backdoor draws...

When you do hit happen to hit 'em, they rarely see it comin'.

When chasing draws, we generally like to factor in the likelihood of getting our bets called should those draws hit. In other words, we consider the implied odds that perhaps make drawing for flushes, straights, or other hands more worthwhile.

Generally speaking, when, say, a flush arrives via running cards on the turn and river, your chances of getting paid off are higher than when two suited cards flop and then a third subsequently arrives. When you hit that runner-runner flush, your opponent will be less likely to credit you with having it and thus perhaps more apt to pay off your river bet.

Of course, you don't necessarily want to start actively seeking out spots to chase backdoor draws. But it is definitely worth being aware of them when they occur.

The possibility presented by a backdoor flush draw (for example) is often worth taking into account when deciding how to play the flop. Particularly in those marginal spots where you find yourself divided between two possible actions -- say, to call or fold, or to call or raise -- the presence of that backdoor draw might be enough to help push you toward a particular play.

Sure, in the case of the backdoor flush draw, it's really just one more "out." Then again, as those crazy finishes in last night's games demonstrated, one out can make a big difference.

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