Intro
My last COTM on position (collaboration with CMV) was pretty long. This time around I’m venturing out alone so this COTM will be much shorter. I plan to just lay out the most basic of ideas and then provide some examples so that those with more expertise than me can comment and expound.


Definition
Blockers are simply cards that you hold in your hand. Since they’re in your hand, they can’t possibly be in the hands of your opponents. It’s information about your opponents that they don’t know you have. We’ll get into the implications of this in a bit.

Example:

Board: A23

We hold: K 5

We block the nuts. Our opponent cannot possibly have a straight flush. He may think he is drawing to one, but we know that he can never get there. This is pretty valuable info that our opponent does not have. Many low level players will chase that one card out. Knowing that they can never get there is a nice advantage to have. This is a pretty extreme example, but it suits the purposes of our definition just fine.


The real discussion to be had here is what do blockers do to your opponent’s range and what can we do with this added info?

I’d like to break this down into two categories.

1. Blockers when facing aggression
2. Blockers when showing aggression.

How do blockers fit into these two situations?



Blockers when Facing Aggression

Example:

Our opponent is a loose aggressive player who loves to apply pressure post flop, but isn’t a total maniac. We raise AKo preflop to $40 and he calls. Effective stacks are $500.

Flop: K73 ($85)
We cbet $50 like good players do and he comes over the top for $175.

Should we call? Go all in? Fold?

Rank your starting hands in order of preference:
AK
AK
AK
AK

To me this ranking seems really obvious, but I see a lot of weird arguments in various threads as to whether it’s better to have the nut blocker against this opponent.


My Ranking



Does your ranking change if you’re up against a nit that doesn't ever get out of line?


My Ranking


I’ll explain my rankings if discussion gets going on this. The point is to realize that the cards in your hand affect the range of the player you’re up against. If the LAG raises all TP, 2P, sets, and flush draws, then having a big diamond in your hand is really going to change the range left over when he raises your flop bet.

There are two things to remember here. You have to recognize what your blockers do to ranges, and you also have to understand what your opponents are doing with those ranges. Having the A blocker against a nit who never raises flush draws really doesn’t change his range all that much. It just changes the equity calc on your end some.

We must also consider stack sizes and SPR. With an SPR of 2, our aggressive opponent is going to be shipping all of his FD’s and weaker Kx’s. In the above example, with SPR of 2 having flush blockers is good because when he goes all in it weights his range more toward Kx, which we have crushed (there’s also a cool thing called back door flushes which really tilt people when we hit).

What if instead, the SPR is 20? He’s probably not raising with his Kx anymore, so having those flush blockers actually hurts us because he’s raising more of a value range vs. our TPTK than he’s raising with FD’s.



Blockers when Showing Aggression

Example:
You call a raise vs. a tight opponent with QQ. His range is JJ+,AQ+ exclusively.

Flop: K43

Your opponent cbets 2/3 pot. You consider turning your Q’s into a bluff by raising. You believe he’ll fold his lower PP’s and AQ, and continue with KK+,AK. How often is that going to work?



Opening range of JJ+,AQ+



Continuing range of sets, overpairs, and TP


His opening range consists of 36 combos. Of those 36 combos, 21 will continue against your raise (58%).

What happens if instead you held K7? QQ is a better starting hand than K7ss obviously, but they are virtually the same if you’re going to raise with each in this spot since your opponent will continue with the same range and you don’t do well against that range with either hand.




Opening range of JJ+, AQ+




Continuing range of sets, overpairs, and TP


This time your opponent has 43 combos in his opening range. Of those 43 combos, he’s only continuing with 15. That means the percentage of times he continues has plummeted to 35%. So, your value comes not from having top pair as opposed to an under pair (QQ), but from the fact that your K blocker has dramatically decreased the odds that he has a hand with which he’ll be willing to call your bluff (you’re not blocking his QQ anymore either).

A more realistic scenario is calling the flop bet, checking a blank turn and then facing a river bet. Picking off the bluff is going to succeed more often when you have the K blocker for the simple reason that he will be bluffing more often due to there being fewer combos of Kx in his range. So, K7 >QQ not because one is top pair and one isn't, but because K7 eliminates value combos from the opponents range.

Semi bluff example:

Your opponent is straight forward except he cbets 100% when heads up and 80% multiway. He cbets regardless of board texture.

V raises preflop and you call with KJ. Heads up. His range is TT+,KJ+. We’re not debating whether you made a good call or not. Let’s just say that you decided to use your positional advantage and his propensity to cbet too much to even things out.

Flop: 932
V bets ¾ pot, which is his standard line.

Why might this be a good time to raise? How does having the K and J change his range? Does it help or hurt? In this situation, you’re not really raising for value (although you might be without knowing it). You’re turning your hand into a semi bluff. We’re not debating whether this is a good play or not. We just want to think about what hands he can have now that the K and J have been removed from his range. Let’s assume he 3bets all of his own flush draws, and calls with JJ+. How does your initial raise look if you instead hold 76?



KJ vs. range




67 vs. range


Just looking at a straight forward equity calculation vs. his opening range to the conclusion of the hand indicates that it doesn't really matter, however, this is not the whole story. This is a good example of a situation where misapplication of stove or other equity programs can be misleading.

A closer look at the equation shows how important those blockers really are vs. his continuing range. We need to figure out if holding blockers changes the frequency that the bluff succeeds without a showdown.



Continuing range vs. KJ



Continuing range vs. 67


With 67, we don’t block any of his continuing range. He’s going to raise 5 times more often when we don’t block his big flush draws (5 combos to raise vs. just 1). He’s also going to call us with over pairs 33% more often (24 combos vs. 18).

Note his tendencies haven’t changed nor has his range changed. All that’s changed is the mathematical probability that he has the cards to perform his standard action. So, we have to rely on our coin flip equity way more often, and we’re smoked by bigger flush draws 5 TIMES more often.

Blockers don’t seem like such a small thing anymore do they?

I want to thank Aesah for helping me think through some of this. He’s a Sith Lord of PLO which uses the concept of blockers a lot more than holdem. If you can incorporate this thinking it’ll help both games. I don’t feel like I think about this enough, so I certainly hope others can add things I haven’t thought of or interject where I’m just wrong. As always I truly appreciate the 2+2 community and hope this helps you guys as much as it helps me.

Nice COTM, and something I don't think about as much as I should.

Something spikeraw mentioned, but you may have blipped over, is that sometimes, you'd prefer not to have a blocker, particularly a NFD blocker. Having that blocker can take a lot of semi-bluffs out of a Vs range, leaving you doing much less well. Also, it can beguile you into loose calls with "I have the nut back-door FD too" logic.

I'd say this thinking is correct against a nit. If he's only making value raises then you can use the extra equity. Against a looser opponent you're just limiting the parts of his range that you want to be up against.

Exactly. Usually people think of it the other way around. "He's a LAG, so having a back door draw against him is great, because he'll be more likely to pay us off, plus his range is wide so every bit of equity helps."

Actually, against LAGs you prefer not to block the part of his range that you're doing well against. That makes his range much more value-y. Against a nit, OTOH, he's not semi-bluffing anyway, so having the "blocker" doesn't actually block a portion of his range, as it was never in his range to start with. The extra equity doesn't hurt, but is not that big a deal.

FWIW, even nits sometimes semi-bluff the NFD, so I don't really agree with the contention that having or not having the NFD blocker doesn't really matter against nits.

I think you're right.

By the way, I'm virtually positive, in almost all real-world scenarios that 76s is a better bluff hand than KJs.

The reason being that when hands like QJ, JT, TT, and 99 fold, and you have KJs, you're folding out a range that you're ahead of (you have 78% equity).

When you have 76s and you make QJ, JT, TT, and 99 fold, you're folding out a range that you're an underdog against (you have 47% equity). Those folds are much more profitable.

Having a smaller continuing range only tells half the picture. More important is our equity against the hands that we made him fold.

You could make that case for 47o. By your logic, that's an even better bluff because it folds out more equity.

I'm pretty sure that OP wouldn't dispute what you're saying. If hands like QJ, JT, TT, and 99 are in the villain's range, then folding them out with 76s is great, where making them fold with KJs doesn't gains us much. But OP's examples were not set up to compare KJs vs 76s as bluff hands in general, but to demonstrate how to think through a situation, using a very specific and very small villain range just for simplicity's sake.

Thanks to the OP for this work, which really complements what I'm reading now in Dynamic Full Ring Poker: Beyond the Basics.


-EF

Great post +1

So we use blockers to narrow down a villains range and to act according to that range in layman'a terms?

For example:

We are on the button and we raise to 20 with As,10s. BB calls who is a tag.

Flop comes 2s, 8s, 10 h

We bet 50, villains shoves for 175.

Our 10 blocks trip 10s, so we only put him on combos of sets of 8's, and 2's since he wouldn't be drawing for the nut flush draw since we hold the As. Is this using the theory correctly?

That's the right idea, but you've narrowed his range too far, imo. V could also have 9sJs, KsXs, Tx8x, etc. Still, there is much less top set, and no NFD semi-bluff in his range due to our blockers.

Main point: Notice how much his range changes with our blockers.

Subpoint: Decide what to do with this info.

Subpoint: Hoping others can get in on the 67ss KJss argument because I think there's some competing ideas. I don't think anyone has completely encompassed the situation yet. We're all bringing pieces to the party and coming up with different conclusions. I wonder what it might look like with everything put together.

Very nice work. Definitely a topic I don't think about as much as I should.

I think this is not quite right, because our blockers affect the denominator too. His opening range is 104 combos. When we have KJs, we block 25 of them. (You said his range was TT+/KJ+, which would mean 30 combos of pairs. I'll assume you meant JJ+, not TT+.) With 76s, we're getting called by overpairs with probability 24/104 = 23%, and with KJs, we're getting called by overpairs with probability 18/79 = 23%. It doesn't actually make much difference, because while we do block some overpairs, we block plenty of AK/AJ/KQ/KJ as well.

Exactly, what makes 76s a "better bluff" is just that it has less showdown equity. Given that we've semibluff raised, we'd obviously much rather have KJs than 76s.

I'm again drawing on my current reading, writing this out in part to test my own understanding.

Point 1: When we semi-bluff, we'd really like to get folds. Our best semi-bluffs should show direct profit (meaning villain folds to this bet or raise enough of the time that even if we lose every time villain continues, i.e., even if we never hit our draw, we are still in +EV territory).

Point 2: The power of the bluff in the abstract is to turn hands with -EV into hands where we get some profit because our opponents fold incorrectly. In this sense, the "best" bluff hand is 72o, because when we can bluff with it successfully, we turn the worst starting hand in holdem into a money maker. But this logic is totally scalable: we can't bluff all the time or win with every single hand. This is why we have to both choose our spots and balance well (against observant opponents).

Point 3: In live games especially (this is me extrapolating from my reading, trying to apply it to LLSNL specifically), we rarely have the situations or the information to bluff 3bet preflop successfully (for example), and since we're never flatting preflop with 47o or 72o, we are basically never going to find ourselves bluffing with these hands postflop. The exception might be at a super tight live table with nits on our left, where we steal almost indiscriminately.

Point 4: Split's major takeaway on bluffing (again, this is from Dynamic Full Ring Poker) is that we should always be conscious of not overexposing our stack. We should bluff, says Split, with "potshots," stabs that should turn a profit on their own. And once we find the situation in which a bluff will be profitable, it matters little what we hold. We may be turning a showdown value hand into a bluff (when our read is that our opponent will fold too much when ahead), we may semi-bluff, and we may run a pure bluff sometimes. But the purity of the bluff doesn't depend on having cards like 47o. Rather, it depends on the certainty in a given situation that we are behind and drawing to few (if any) outs. Example: Imagine we've three bet with something like JJ in position and gotten called by someone so tight that his continuing range is QQ+/AK. (No, this isn't necessarily realistic in LLSNL!) The flop comes K94, rainbow. We'll, we know we are behind, so if we bet or if we raise when bet into, we are on a pure a bluff, even though our hand is a biggish pocket pair. (Let's leave aside the likely EV of such a bluff spot.)

Takeaway: Split's suggestion that as a hand develops we start thinking our hands in the categories of pure value; showdown value; semi-bluff; or bluff helps us to see that the "best" bluffs aren't necessarily those with the worst two cards in the hole.

Nice thread

this made me very happy i looked at my non-subscribed threads!!!!! A++

Great article man. Im gonna work on incorporating this into my game but that doesnt seem easy because i am not on that level of ranging yet. I just know the basics. But this totally opened my eyes. Until now i just thought blockers as my opponents having slightly less of a chance of hitting a flush on me or something. And now that seems like a very donkish way of thinking.

I'll throw in my 2 cents.

I think this COTM does an excellent job of explaining the concept of blockers.

I almost never take blockers into consideration in the games I play. Maybe this a leak, but I'm not so sure. My reads on villains are probably not as accurate as I would need them to be to incorporate blockers. I think I'd just wind up FPS/leveling myself into mistakes.

I play in pretty weak games. I NEVER play with a V who is 3-betting flush draws, so while I understood the example with the KJs and 67s, it's more of theoretical example to me.

The first example where we're blocking nut flushes and straight flushes seems like a more real world example. The Vs I play with love, love, love to draw to one card straight flushes.

There's probably only two times I regularly factor in blockers:
1. When the ace of a flush draw is involved.
2. When I'm blocking two pair and sets

If I have KT and the board is KT3 and I'm facing aggression from a villain, I'll discount KK, TT, and KT from his range.

My Vs suck though. I'm guessing that as you play more difficult competition and move up the limits, you have to refine smaller edges. I'd be willing to bet that a mastery of blockers is more important in a $5/$10 game than a $1/2 game. Maybe not. I'm sure I'm missing some spots where blocker awareness would help me at $1/2.

I'm going to look for ways to use blockers more often today though.

My two personal concepts of the day for today:
1. Pay attention to how my holdings affect V's ranges
2. Continue to pay attention to Joe Navarro's thumb tells

Thanks for the good COTM though, Spike!

Nice table selection discipline. We can still semi bluff for value w our
Kt vsrite opps.

If you have 88 on a T9762 board and you are facing a nit who only raises with the nuts, having blockers against J8 still means that he beats you with 100% of his raising range. People who don't understand blockers think that having two eights in your hand always makes it less likely you are beat when raised, when that is not the case against some opponents.

The important thing is to realize that it's less likely that you'll get raised/be chopping. So, you can bet/fold with confidence in that situation. If he's capable of calling with 2p/sets, then you're blockers are really polarizing his range.

His raising RANGE hasn't changed really. The percentage of his total range that is his raising range goes down quite a bit though.

Good observation.

Nice COTM. Thank you for putting it together spike.

Like others ITT, I too need to think about the blockers in my hand more and how it impacts the villains' range in any given hand.

This is very well written and for a very complex subject

+ 1 mirrion

May have missed it, but during our decision to 'decide what to do' shouldn't we be aware of the strength of our blockers (not just that we have them) in deciding what size bet to put out there that gets them to continue?

Obv we always want to 'charge' value for an opponent to continue, but wouldn't it make sense that we 'need' to reduce our bet size to 'allow' our opponent to feel priced in even though we know we are still putting them in a -EV position?

Although 'outs' and 'range' are 2 different entities, yet releated ... Does it make sense that we should 'only' c-bet 50% PSB when we figure out that we block our opponents range down to 35% of that range?

I might be silly here, but it seems to make sense that since it's less likely that our opponent hit his range that we need to make it 'easier' to call a bet? Granted our opponent doesnt know that he has outs missing .. this issue is can we feel comfortable giving away some of that knowledge by making our opponent feel more priced into a call. GL

If I'm interpreting correctly:

When holding JJ on a J65 board, we know v's flush draw with A2 only has 25% instead of the 33% he thinks he has, so we could profitably let him draw for 30% an he's happy.

Yes, we could but he doesn't know that so we might as well make him draw for te higher amount since his perceived equity is what we can target. His actual equity doesn't matter too much when choosing a bet size that hell call.

When it comes to blockers, you can targe other parts of his range more heavily since his odds of having those is greater. So, I guess blockers might effect which Japanese city I decide to drop on, but not necessarily the size of the fat boy.

If blockers push my target toward something that requires a bigger or smaller bet then I would say they affect sizing.