Blockers And Backdoor Draws

Lately I’ve been watching some instructional videos made by elite players. Something I noticed about the videos is that they tend to cover fairly advanced ideas in brief snippets. The coach will go through a hand he played, and he’ll mention that he bluffed with this particular hand because of that backdoor draw. And he chose that hand to bluff with because it blocks this hand. And then it’s on to the next hand.

I realized that if you aren’t already very up on the latest poker theory, you’re likely to get lost by the thought process. With this article I hope to bridge that gap just a little by explaining two common themes in advanced analysis.

Backdoor Draws

Modern poker theory focuses on frequencies and hand ranges. In any given situation, elite players are most concerned with the frequencies of their actions. When my opponent bets this flop, how often should I be raising, calling, and folding?

Once the frequencies are hammered out, it’s time to construct hand ranges. For example, if I’ve decided to raise the flop 10 percent of the time, call 65 percent, and fold 25 percent, which hands do I choose for each action?

Some hands are obvious. OK, I’ll raise bottom set. I’ll fold a no-pair/no-draw suited connector. I’ll call with this middle pair.

But once you’ve placed the obvious hands, you have a murky mix of hands that could reasonably be played each of several ways.

What do you do with a gutshot, for instance? You could argue for raising it, since gutshots usually have little showdown value, but they give you a chance to make the nuts. A gutshot can make sense as a bluffing hand.

Or you might call with it. A gutshot is a low-but-not-zero equity hand. It might make for a good hand to float with.

Or you might just fold the gutshot.

Frequently with these hands you will want to split them among the possibilities. I’ll raise some of my gutshots and call with other ones. The next step is to try to find the split that optimizes the value of the full range of hands. This is where backdoor draws come into play. Very frequently they act as a powerful tiebreaker in this process.

Say you open for $20 in a $2-$5 game, and your opponent in the big blind reraises to $60. You call.

The flop comes 9 5 4. Your opponent bets $80 into the $122 pot.

Many of your hands are going to be two overcards. Many of your opponents’ hands will also be two overcards. You need to defend against the bet with some overcard hands. Overcard hands with backdoor draws should be chosen ahead of ones that lack backdoor draws.

Compare K Q to K Q. The first hand has a backdoor-flush draw and the second doesn’t. Because of the difference, I will never fold the first hand. I’ll either be calling or raising with it. The second hand, I will rarely raise. Usually I’ll either call or fold.

Compare J 10 to J 10. The first hand has two backdoor draws and the second only one. The first hand is one I will frequently choose to bluff-raise with. The second hand is likely a fold or possibly a call.

You might say, “But backdoor draws come in only four or five percent of the time. What’s the big deal?”

It’s true. They come in only a few percent of the time. But their impact is much bigger than that, because when they do come in, the pot is often massive.

My opponent bet $80 into the $122 pot on the flop. Let’s say I raise to $200 with K Q. He calls. There’s $522 in the pot.

The turn is the 2 for a board of 9 5 4 2. He checks, I bet $360, and he calls. There’s $1,242 in the pot.

The river is the A. I just made my backdoor flush in a pot that’s already enormous. If I start out by raising with hands that have no backdoor draw potential, this can never happen. The best hand I’m likely to have by the end is one pair. In a massive pot, one pair usually won’t be good enough.

So sure, it’s a small probability outcome, but it can be a massive money swing when a backdoor draw comes in. This reality means that when you’re choosing marginal hands to call or raise with, you nearly always want to choose ones with backdoor draws before those without.

Finally, if you consistently choose hands with backdoor draws in them to push on the flop, then every time a backdoor draw comes in, you’re a legitimate threat to hold it. For instance, say you actually hold the flopped flush draw of K Q on the 9 5 4 board. The turn and river run out the 2 and A. The pot is the same $1,242.

Your opponent checks to you. You could shove for $1,000-plus and credibly represent the backdoor draw since you’d play K Q the same way you’d play K Q. This action is incredibly threatening to your opponent if he’s been calling along with a hand like K K.

Blockers

A blocker is a card in your hand that would play a significant role in your opponent’s range if it were available. The simplest example is the bare ace of the flush suit with three to a flush on board. Holding that card blocks your opponent from holding the nuts, and it significantly reduces the chance that your opponent has any flush. If you are trying to fill out a bluff-raising range on such a board, you would strongly prefer hands with the ace blocker to those without.

Blockers come into play in nearly every bluffing/bluff-catching scenario. Say you’re playing the hair-raising hand I described earlier, but you’re in the blind. Your opponent opens for $20, and you reraise to $60 from the big blind. The flop comes 9 5 4. You bet $80, get raised to $200, and you call.

The turn is the 2. You check, your opponent bets $360, and you call.

The river is the A. You check, and your opponent bets $1,000.

Compare A 9 to A 9. Both hands make top two-pair, but with the huge river bet, your opponent is repping a stronger hand than that. Your two pair is a bluff-catcher. If you call, you’ll see either a flush (or possibly a straight), or you’ll see a bluff.

Be more inclined to call with A 9 than A 9. If your opponent is bluffing, a big set of candidate hands would be flush draws. A big set of those include the A. If that card is in your hand, it means your opponent isn’t bluffing you with it.

Blockers are a simple, but powerful concept. Bluff with hands that include cards that would be in your opponent’s calling range. Call with hands that don’t include cards that would be in your opponent’s bluffing range. ♠

Ed’s newest book, Playing The Player: Moving Beyond ABC Poker To Dominate Your Opponents, is on sale at notedpokerauthority.com. Find Ed on Facebook at facebook.com/edmillerauthor and on Twitter @EdMillerPoker.